Refer to figure.
A cold front occurs when cold air replaces warm air. The denser cold air overtakes and displaces the less dense warm air, sliding under it and forcing the warm air to rise.

The weather band associated with a cold front is typically 30-50 NM wide.

The first sign of the approaching front is a line of towering cumulus or cumulonimbus clouds with associated showers and gusts. This is due to the warmer sector air being forced upwards triggering convective activity.

After the front passes, the cloud base rises, the clouds thin out, and precipitation decreases. Behind the front, the southward-moving polar maritime air is warmed from below, making it unstable. This instability usually produces scattered, isolated cumulus clouds.

As for the other options;

• Warm fronts do not usually produce cumulus type clouds, instead they produce stratified clouds, due to very stable air.
• A col produces very calm winds and little air mixing, often with no clouds, but with very occasional thermal thunderstorms on hot days with unstable atmosphere.
• Anticyclones are regions of high pressure, and are therefore areas of air subsidence (descending air), and therefore do not give rise to convective clouds.