C5 is as good as any move and is played by about the same number of 2700+ players as d5.  The two are equal in value and they usually transpose to each other after 5... c5 6. Nf3 d5 or 5... D5 6. Nf3 C5

This is a very unquic opening. It has pros (good) and cons (bad). Black has castled bu white has amore control center. Blacks best move should be c5. Are there any other options for black?

while most GM's do favour the bishop pair for exactly the reasons you have specified.  it is important not to fall into this thought process that there is only one way to play chess.  knights can be superior to the bishop pair under the right conditions, how you create those conditions is what makes a great chess player.

material is even and you have simply made a trade, giving up your dark squared bishop to disrupt your opponets pawn structure and leave him with doubled pawns.  just as in the sicilian defence white trades a center pawn for faster development.

you should also note that in some lines black opts to keep his dark squared bishop depending on how play follows.  while this defense is very different from whites ruy lopez opening, it does follow some of the same principals.  develop kingside bishop and knight first and castle early.

Whenever a bishop attacks a knight early in game, as in this one, I've often seen players take the knight. I've read that bishops are more valuable in the endgame, when the open board affords them more mobility. Therefore, I question the soundness of making such an exchange early in the game when it could come back to bite you in the end. What ya'll think?

@_@

Those doubled pawns aren't weak.  There would be no slight disadvantage.  If anything white is slightly better for possessing the bishop pair.

The position is imbalanced and an interesting struggle is upcoming but there is absolutely NO advantage to black.

By taking ur c3 knight u will end up with a double bond and have a slight disatvantage. So to prevent this u can move ur black bishop to d2 which allows u to bring the bishop into the game or bring up ur A pawn but this is not as effective.

Whenever I play an Indian game as white, black invariably seems to trade his dark squared bishop for my c3 knight.... why is that?