Comets are typically ?

a.) chunks of ice that begin to vaporize if they pass close to the sun.

b.) slushy mixtures of liquid and ice.

c.) gaseous bodies from which some of the gas is pushed out by the sun to form a long tail.

d.) chunks of rock that are generally a few tens of kilometers in diameter.

??? i appreciate those that help!!! <3

p.s. this subject is astronomy it just doesnt have it as a subject option nor a science option....