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 XXXXXXXXXXresidents were polled. Let XX denote the...

 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 900900 residents were polled. Let XX 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+((√900)/2))/900 . The estimator p^ has bias

Which one is correct?

1) 1/30
2) 30/2
3)  0, so unbiased.
4)  1/900
5)  1/(2×30)