-40 through 40 = 0
41 through 60 is ten sets of 101. That's 1010.

Answer choice C.
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We want to find the sum: (-40) + (-39) + (-38) + . . . . 38 + 39 + 40 + 41 + 42 + 43 + . . . 58 + 59 + 60

In the red sum, we can see that every pair of positive and negatives value with the same magnitude (e.g., 39 and -39) cancel out for a net sum of zero.
So we have: 0 + 41 + 42 + 43 + . . . 58 + 59 + 60, which means we need only find the sum of the blue integers.

The number of integers from 41 to 60 inclusive = 60 - 41 + 1 = 20
If we add up the 20 values by pairing values from both sides of the sum we get: (41 + 60) + (42 + 59) + (43 + 58) + . . . etc.
Simplify to get: 101 + 101 + 101 + . . .
Since we have a total of 10 PAIRS, we know that: 101 + 101 + 101 + . . . = (10)(101) = 1010

Answer: C
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