The correct answer would be B nuclear fission because an atom is splitting into two large fragments of comparable mass
n = m/M = 2/18 = 1/9 ~0,1 mol
I believe the answer is compound B may have a lower molecular weight compared to compound A.
At the same temperature, lighter particles of a compound have a higher average speeds than do heavier particles of another compound. Thus, particles of compound B are lighter than those of compound A and thus they have a higher average speed, hence evaporating faster compared to compound A.
The answer should be Aegle marmelos