Concept:The underlined word is "unalloyed", which means complete, pure, and not mixed with anything else.
We need the word that is most nearly opposite in meaning and can correctly fill the gap.
Explanation:"Unalloyed" means total and unreserved, for example, "unalloyed support".
So its opposite should suggest hesitation, doubt, or lack of firmness.
"Wavering" means becoming weaker, hesitating, or faltering.
Thus, "wavering support" is the direct opposite of "unalloyed support".
The other options are not suitable: "strict" means demanding, "clumsy" means awkward, and "alterable" means changeable.
None of these gives the required opposite meaning.
Therefore, the correct word to fill the gap is "wavering".
Answer:B. wavering