The planet mercury has a diameter of 4,878 km whereas the moon has a radius of 1736.5 km. which object is larger and why?

First, to be able to compare these two things, you have to either find the radius of Mercury or find the diameter of the moon. I choose finding the diameter of the moon because it seems easier.

Diameter=radius*2
Diameter=1736.5*2=3473

The moon has a diameter of 3473 km.

Since Mercury's diameter, 4878km, is greater than the Moon's diameter, 3473km, Mercury is larger.

Hope this helps!

c is the correct answer