What is the difference between Vx and Vy in projectile motion?

Ithink it is letter b, i may be wrong but i think that is the answer

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.

Answavelength; amplitude;