Given the Following EVENTS $($NODES$)$ and TIMES $($days$)$

Activity

Start

Finish

OPTIMISTIC

MOST LIKELY

PESSIMISTIC

A

$1$

$2$

$41$

$50$

$59$

B

$1$

$3$

$54$

$60$

$66$

C

$2$

$4$

$58$

$70$

$82$

D

$3$

$4$

$32$

$41$

$44$

What is the estimated slack time for activity D$?$