A predicate adjective is the first adjective that follows a linking verb which connects two parts of a sentence (in this case, that verb is 'was'). So, the first adjective after was is 'sleek', so D is the correct answer.
The correct answer for the question that is being presented above is this one: "the extent to which the poem achieves its intended objective." A dramatic constructionist would critic focus on when interpreting this poem such as <span>the extent to which the poem achieves its intended objective</span>
3 reasons to support your claim
I might be wrong, but I think it's a verb. :^]
