Activity Predecessor Duration

Optimistic Most Likely Pessimistic te s s$2$ Critical $($Y$/$N$)?$

A $-81420????$

B A $31221????$

C B $81114????$

D B $666????$

E B $81420????$

F C$,$ D $81114????$

G D $21024????$

H E$,$ G $41016????$