1. Wonder Girls are doing their best to be a world star.

Question

2. Wonder Girls are doing her best to be a world star.
3. Wonder Girls are doing the best to be a world star.
[Which one is grammatical?]

Answer 1

Wonder Girls was a girl group composed of five girls.

Answer 2

I assume Wonder Girls are more than one girl.

The correct statement would be:

Wonder Girls are doing their best to be world stars.

Answer 3

Or --
The Wonder Girls group is doing its best to be a world star.

Answer 4

Have you ever wonder why when addressing Nigeria,they make use of "her"...its mostly like a word that best defines reproduction as a group....i think #2 is grammatically correct