The correct answer is c. Order of operations indicates that multiplying the fraction 9/5 times C occurs first, and then the addition. We need to be careful to use "floating point" division, as opposed to the integer division that will occur if we use the division operation with two integers (such as 9 and 5). Expressing one of those values as a double value solves the problem. Alternatively, you could just use 1.8 * C + 32 to avoid calculating the fraction altogether.