Hydrogen and Lithium React Very Differently, Although They Are Both

Multiple Choice

Hydrogen and lithium react very differently, although they are both members of Group 1. What is the primary reason for this difference?

A) Metallic character increases going down a group.
B) Electron affinity increases going down a group.
C) There is a very large difference between the atomic radii of H and Li.
D) Ionization energy increases going down a group.
E) Electronegativity increases going down a group.