If 7 is subtracted from a number and the result is 50, what is the number?

To determine the correct number, we can set up the equation based on the information provided in the question. Let "x" represent the unknown number. According to the problem, if we subtract 7 from this number, the result is 50. This can be expressed with the equation:

x - 7 = 50.

To solve for x, we need to isolate it by adding 7 to both sides of the equation:

x - 7 + 7 = 50 + 7,

x = 57.

Thus, the value of the unknown number is 57. This aligns with the choice provided, confirming that subtracting 7 from 57 results in 50, which is the condition given in the question. Therefore, 57 is indeed the correct number.