11. Use several square tiles of exactly the same shape to pave a square floor. If the two diagonals of the floor are paved with a total of 37 tiles, then the total number of tiles needed to pave the entire floor is ( ).
(A) 148
(B) 324
(C) 361
(D) 1296
(E) 1369
11. C.

Let the number of tiles needed for each side of the square floor be $x$. Then the diagonal also needs $x$ tiles.
$$
\text { Thus, } 2 x-1=37 \Rightarrow x=19 \text {. }
$$

Therefore, a total of $19^{2}=361$ tiles are needed.