The pessimistic estimate for project completion is $60$ weeks; the optimistic completion

estimate is $36$ weeks. With a most likely completion of $48$ weeks, what is the estimate for

the possible range of completion to a $95\%$ confidence level?

a$.$ Between $42$ and $54$ weeks

b$.$ Between $38$ and $58$ weeks

c$.$ Between $45$ and $51$ weeks

d$.$ Between $40$ and $56$ weeks