The correct match for the reactions P-S with the names of cyclizations I-IV is
Names of cyclizations:
I. halocyclization
II. Nazarov cyclization
III. radical cyclization
IV. electrocyclization
1
P-IV; Q-I; R-II; S-III
2
P-II; Q-I; R-IV; S-III
3
P-IV; Q-II; R-III; S-I
4
P-II; Q-I; R-III; S-IV