The operations manager of a large production plant would like to estimate the mean amount of time a worker takes to assemble a new electronic component. Assume that the standard deviation of this assembly time is 3.6 minutes.

b) How many workers should be involved in this study in order to have the mean assembly time estimated up to ±15 seconds with 90% confidence?

A.  558 workers need to be involved to achieve the desired precision.

B.  797 workers need to be involved to achieve the desired precision.

C.  12 workers need to be involved to achieve the desired precision.

D.  797 workers need to be involved to achieve the desired precision.