A--- They are five. Allah the Almighty mentioned them on two locations in His Glorious Qur'an:

The first: in Surah Al-Ahzab that reads, {And (remember) when We took from the Prophets their covenant, and from you (O Muhammad (Peace be upon him» and from Nuh (Noah), Ibrahim (Abraham), Musa (Moses), and `Isa (Jesus) son of Maryam (Mary). We took from them a strong covenant}. (Al-Ahzab, 7)

The second: in Surah Ash-Shura that reads, {He (Allah) has ordained for you the same religion (Islamic Monotheism) which He ordained for Nuh (Noah), and that which We have revealed to you (O Muhammad (Peace be upon him)), and that which We ordained for Ibrahim (Abraham), Musa (Moses) and `Isa (Jesus) saying you should establish religion (i.e. to do what it orders you to do practically), and make no divisions in it (religion) (i.e. various sects in religion). Intolerable for the Mushrikun, is that (Islamic Monotheism) to which you (O Muhammad (Peace be upon him))

call them. Allah chooses for Himself whom He wills, and guides unto Himself who turns to Him in repentance and in obedience}.

(Ash-Shura, 13)