Option 1 -> frequently - means happening often or many times, which contradicts the irregular nature of sporadic occurrences.
Option 2 -> continuously - means without stopping or interruption, which is the opposite of sporadically.
Option 3 -> unpredictably - emphasizes the inability to forecast when something will happen, but doesn't capture the infrequent, scattered nature of sporadic events.
Option 4 -> occasionally - means happening from time to time at irregular intervals, which accurately reflects the meaning of sporadically.
Hence, Option 4: occasionally -> "Sporadically" refers to something occurring at irregular intervals or infrequently, and "occasionally" best captures this meaning of intermittent, scattered occurrences of fighting rather than constant or frequent conflict -> correct