AMC 12 2017b Problem 21

Last year Isabella took $7$ math tests and received $7$ different scores, each an integer between $91$ and $100$, inclusive. After each test she noticed that the average of her test scores was an integer. Her score on the seventh test was $95$. What was her score on the sixth test?

\textbf{(A)}\ 92 \textbf{(B)}\ 94 \textbf{(C)}\ 96 \textbf{(D)}\ 98 \textbf{(E)}\ 100