I'm trying to figure out the answer but i'm getting nowhere. me understand how to calculate it.

You don't need to pay attention to the area in this case. We are trying to figure out the mass. What do we need? F= m*a (Force= mass * acceleration of gravity). acceleration of gravity on earth: 9.81m/s^2. so 15000= m*9.81. We need m (Mass) so m= 15000N/ 9.81m/s^2 = 1529.051988 ≈ 1529.05kg.
the mass of the empty plane is therefore 1529.05kg

No because scientist are still changing there mines today so they are not correct to this day

The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings.