In a network, what is total float equal to ?
(a) LFTj – ESTi + ti – j
(b) ESTj – LFTi – ti – j
(c) ESTj – LFTi – ti – j
(d) LFTj – ESTi – ti – j
where, LFT = latest finish time of an activity; EST = earliest start time of an activity; ti–j, = time of activity i–j.