The correct answer is A. near.
When an enemy comes near a betta fish, the fish will puff out its gills to make it appear to be larger than it really is. This is a defensive mechanism that helps the fish to scare away predators.
The other options are incorrect because they do not describe the situation in which a betta fish would puff out its gills. Option B, far, is incorrect because a betta fish would not puff out its gills if an enemy is far away. Option C, in, is incorrect because a betta fish would not puff out its gills if an enemy is inside its tank. Option D, None of the above, is incorrect because one of the options is correct.