Select the word or phrase which best expresses the meaning of the word typed in bold : The liberal school of thought trusts in education reform, and the sporadic use of force to remedy the depravity of certain isolated individuals or groups.

Op 1: Infrequent, irregular 
Op 2: Persistent, constant 
Op 3: Continuous 
Op 4: Sparing

Solution:

Option:1 (Infrequent, irregular)

occurring at irregular intervals or only in a few places; scattered or isolated.