A work centre had planned outputs of 10,15,13, and 20 hours with actual outputs of 12, 14, 13, and 18 hours. The cumulative deviation in output is

A) 0.
B) 1.
C) -1.
D) 58.
E) unable to determine with given information.

The cumulative deviation is calculated by adding up all the deviations between actual and planned outputs.

For the first planned output of 10 hours, the deviation is:
actual output - planned output = 12 - 10 = 2

For the second planned output of 15 hours, the deviation is:
actual output - planned output = 14 - 15 = -1

For the third planned output of 13 hours, the deviation is:
actual output - planned output = 13 - 13 = 0

For the fourth planned output of 20 hours, the deviation is:
actual output - planned output = 18 - 20 = -2

Adding up all the deviations:
2 + (-1) + 0 + (-2) = -1

Therefore, the cumulative deviation is -1, which means that the actual output was 1 hour less than the planned output overall. The correct answer is C.