The operator * is prefixed to an iterator to

a. Multiply the element in the container
b. Extract the element in the container to assign to it only
c. Extract the element in the container to fetch its value only
d. Extract the element in the container as either an l-value or an r-value
e. The * is overloaded to perform addition, so this operator moves where the iterator points by a number of elements.

Part d) is correct.
Explanation: Part a) is wrong, the operator * as used with iterators is unary prefix operator. Part b) is wrong as it omits use as an r-value. Part c) is wrong as it omits use as an l-value. Part e) is wrong for the same reason Part a) is wrong.