This question can be answered only by looking at options, ofcourse answer has to be (A) or (B) because a grammar cannot be both ambiguous and unambiguous. And option (D) also says grammar is unambiguous. Thus (A) has to be answer.
And non-determinism is a problem when we don't know which production to take to get the required string. And Left-factoring is used to remove non-determinism(not ambiguity). So, it may be the case that a grammar is not ambiguous but needs left factoring.
Consider: $S \rightarrow aa | ab$ ($\color{green}{not\;ambiguous\;but\;needs\;left\;factoring}$)
And there is not doubt that $\color{navy}{S \rightarrow aSa\;|\;bSb\;|\;a\;|\;b\;|\; \epsilon}$ generates all even and all odd length palindromes, and for every string only one parse tree can be given. So, this grammar is unambiguous.