Entropy is a/an

Answer: Option D

Since entropy is obviously a point or state function by its definition itself.
If we see the following steps on how we arrived to entropy it will be clear that entropy is a state function:
For, reversible heat engines working under same thermal reservoirs since,
$$\begin{array}{rl}& \oint \frac{\partial Q}{T}=0\\ & \Rightarrow \frac{\delta Q}{T}=dS\end{array}$$
Since, $$\frac{\delta Q}{T}$$   is a path independent quantity we designated it as a property which is nothing but entropy.