In a study to estimate the proportion of residents in a city that support the construction of a new bypass road in the vicinity, a random sample of 1600 residents were polled. Let X denote the number in the sample who supported the proposal. To estimate the true proportion in support of the plan, we can compute p^=X+1600?/21600. The estimator p^ has bias
A. 1/(2×40).
B. 40/2.
C. 1/40.
D. 1/1600.
E. 0, so unbiased.