The Atomic mass if hydrogen us 1.008 amu. The reason that this value is not a whole number is that A. The Mass of hydrogen is the sum of the masses of the protons and electrons in the atom
B. Hydrogen has more than one isotope
C. Hydrogen only exists as a diatomic molecule
D. The Mass of a proton is not exactly equal to 1 amu

I'm pretty sure its c

Explanation:

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6