The ubiquity of God cannot be questioned.

Answer: Option C

Greatness : the quality of being great; eminence or distinction.
Mystery : something that is difficult or impossible to understand or explain.
Omnipresence : the state of being widespread or constantly encountered.
Existence : the fact or state of living or having objective reality.
Ubiquity : the fact of appearing everywhere or of being very common.

Synonym of Ubiquity is Omnipresence