What are earth’s plates currently drifting on?

a. large rock formations
b. mantle currents
c. pangaea
d. water currents

One of the brightest comets of the 20th century was comet hyakutake, which passed close to the sun in early 1996. the orbital period of this comet is estimated to be about 30,000 years. find the semi-major axis of this comet’s orbit. compare it to the average sun-pluto distance and to the distance to alpha centauri, the nearest star to the sun, which is 4.3 light-years distant.

Does anyone know the answers for these

As water is cooled from 4 c to 0 c its density