Fog is common around Newfoundland coast because

Answer: (b) Warm and cold currents meet

The warm Gulf Stream meets the cold Labrador Current, producing thick fog.

The idea

Fog forms when moist air near the surface is cooled to saturation. Air moving from warm water over colder water can lose heat from below and form tiny suspended droplets. A warm-cold current boundary therefore favours sea fog. It is the cooling of moist air, not the collision of water itself, that produces fog.

Warm current supplies heat and moisture to air → Moist air moves over colder water → Air cools from below → Temperature reaches the dew point → Vapour condenses into suspended droplets → Advection fog forms near the current boundary

Why the others are wrong

(a) Icebergs add cold, but the main cause is currents meeting.

Also know

The Grand Banks off Newfoundland combine a shallow shelf with the Gulf Stream-Labrador meeting region. Oyashio and Kuroshio form another warm-cold current boundary near Japan. Radiation fog results from night-time land cooling, while advection fog needs moist air moving over a colder surface. Nutrient supply and shelf conditions help explain the associated fishing grounds.