Use the below description for the next FIVE questions:

Consider the following project for constructing a manufacturing plant

Activity

Designation

Immediate predecessor

Time $($in months$)$

Site development and construction of factory building

A

$-$

$12$

Fabrication and procurement

B

$-$

$16$

Alignment and installation of Machinery

C

B

$7$

Electricity and plumbing work

D

A

$8$

Finishing work on factory building

E

A

$6$

Interior work of the factory

F

C$,$D$,$E

$4$