What is the definition of the latest completion time (LCT) of a project activity? 

a. LCT(A_i) = Max{LST(A_j) for which A_j is a successor of A_i} 

b. LCT(A_i) = Min{LST(A_j) for which A_j is a successor of A_i} 

c. LCT(A_i) = Max{LST(A_j) for which A_j is a predecessor of A_i} 

d. LCT(A_i) = Min{LST(A_j) for which A_j is a predecessor of A_i}