Final answer:
A small mass of magma loses heat a. faster than a large one due to their surface area-to-volume ratio.
Step-by-step explanation:
The correct answer is a. Faster. A small mass of magma loses heat faster than a large one. This is because smaller objects have a larger surface area-to-volume ratio, which means they have more surface area relative to their mass.
As a result, more heat can be transferred from the small mass of magma to its surroundings, causing it to cool down at a faster rate compared to a larger mass of magma.