The acceleration of any particle due to the force of gravity alone doesn't depend on the mass so the answer is a.Whether or not the mass is on an inclined plane doesn't matter in the least bit. we can prove this by calculating the acceleration mathematically :
$F = ma = mg\sin \theta$
$a =g\sin \theta$
As you can see,the acceleration depends only on the angle of the incline and not on the mass of the block.