The factor that does not help determine whether a volcanic eruption will be explosive or relatively quiet is the composition of the lava.
On the other hand, the composition of the magma, the temperature of the magma, and the amount of dissolved gases in the magma are quite important for determining this.
I would say A since it is closest to the mouth of the volcano and says 20 cm
You might put harmful toxins in the beach or into the ocean which would kill wildlife
