Correct Answer - Option 4 : Gallant : Coward
The pattern followed here is:
Incessant : Intermittent → Intermittent is an antonym of Incessant.
Incessant → Ceaseless
Intermittent → Irregular
Similarly,
Gallant : Coward → Coward is an antonym of Gallant.
Gallant → Brave and noble
Coward → Discourteous
Hence, Gallant : Coward is the correct answer.