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 $900$ 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 $\hat{p} = \frac{X + \sqrt{900}/2}{900}.$ The estimator $\hat{p}$ has bias

A. $1/900$.
B. $30/2$.
C. $1/(2 \times 30)$.
D. 0, so unbiased.
E. $1/30$.