Task: Question Answering
Input (English): Which of the following expressions must be positive for all values of a and b?
(A)\(a + b\) (B)\(a^2 - b^2 + 10\) (C)\(a^2 + b^2 + 1\) (D)\(a^3 + b^3 + 16\) (E)\(a^4 + b^2 + a^2\)
Output (English): C