Answer is A).
In apriori algorithm ===>
It occupies large space due to more candidates and hence execution time is more because of more generation of candidates so every time there is scanning , it leads to generation of çandidates.
In FP tree growth method ===>
It has no candidate generation , so requires low memory and hence scaaning is not done multiple times , hence low execution time
Both are used to find frequent patterns , but FP tree method is more eficient to find difficult,frequent patterns in large database .