Consider an External Solar System in Which There Are Three

Multiple Choice

Consider an external solar system in which there are three terrestrial planets.All are located far from other objects, so tidal forces aren't significant.If planet A has a radius of 1 Earth
Radius, planet B has a radius of 2 Earth radii, and planet C has a radius of 3 Earth radii, which
Planet has the highest chance of having at least a partially liquid core and a detectable
Magnetic field?

A) planet A
B) planet B
C) planet C
D) They all have the same likelihood of having a liquid core.
E) None of these planets should have a liquid core because they all should have completely solidified.