Answer:
a. meteoroid, meteor, meteorite
Explanation:
The meteoroid, meteor, and meteorite, are terms that very often are mistaken and are used for a single thing, but in practice they are different, despite having the same basis.
All three, as mentioned, have the same basis, they are the same body, just that the differences occur because of the processes through which the space body goes through.
The meteoroid is a term used for the space body while it freely floats into the interstellar space. The meteor is a term used for when the space body enters the Earth's atmosphere and burns, which can actually be seen in the night sky easily. The meteorite is a term that is used for the piece of the space body that managed to reach the surface of the Earth, but more often than not they burn totally and fall apart while passing through the atmosphere, so the meteorites are much rarer than the previous two.
