Which starter should i choose in platinum and why?

Piplup and Chikorita

Why?

Okay well first up is Roark right?
So that way if one of the 2 faint あなた have the other to use.

Gardenia is a 草 type leader but if あなた get Chikorita to bring her Pokemon down then send Piplup out with a flying 移動する there あなた go she is down and out.

Fantina and Maylene

They'd be battled normally seeing no starter type matches ghost.

Crasher Wake

Send out Chikorita.

Byron

Now Piplup should get used.

Candice

I'd recommend Piplup for battling her but Chikorita can be used

Volkner

Okay now both Pokemon should take action against him but if あなた evolve your Pokemon によって now あなた should have Empoleon and Meganium によって now so go with a full throttle attack!

Aaron

Use Piplup with flying type moves.

Bertha

Chikorita should go now against her but あなた can use Piplup too

Flint

Okay now for Piplup again

Lucian

Now its time for using both but Lucian may get his Mr.Mime too use Reflect または Light Screen または maybe both so his defense may be higher than the 3 you've beaten.

Cynthia

Just pay attention to which Pokemon she is sending out then make your move

Galactic Grunts

They normally use poison and bug type Pokemon so あなた know what too expect and for bug types use Piplup with a flying type attack

Mars

Okay at first her team is Purugly and Zubat so get ready for a full throttle attack against her!

Saturn

Piplup should be used against his Toxicroak then the rest should be the same again full throttle!

Jupiter

Now if I remember right she has two Pokemon first time around both poison so best using Piplup for her

Cyrus

Now I found him the hardest trainer too beat in the game but were あなた catch Giratina use Piplup first for his Houndoom but あなた have to be careful as if I remember right it knows Will-O-Wisp

Your Rival

Now this is were I with I 発言しました Piplup and Cyndaquil but 草 vs. 草 but he does I thing have water type Pokemon Chikorita can defeat and it would be wiser for Chikorita too vs. Turtwig seeing that can be dangerous for Piplup

Sorry that sounded like a guide that was not intended but I couldn't think of an easier way and I suck at explaining but I am probably wrong

Cintaquil & Tertwig-Why?Because those two make beating the leaders,the elite four and the game way easier!Their type match~ups come in handy too!Also their evelutions are preaty strong and Learn better attacks!Trust me.I have done this before

Chikorita and Chimchar. Why? Well, because u can beat roark easily (rock type). Gardenia (grass type) use Chimchar (or Monferno). Fantina (ghost type) Just use your Pokemon. Maylene (fighting pokemon) catch a starly in the beggining of the game and evolve it to either staraivia (or staraptor if あなた trained it hard enough) and use moves like aerial ace of wing attack. Crasher Wake(water type)
use Bayleaf (or meganium if あなた evolved it). Byron
(steel type) use infernape. Candice (ice type) use infernape または other strong 火災, 火 types that あなた caught. Volkner (electric type) use any ground または rock type pokemon that u caught and use meganium. those are my reasons.