Which statement is true about warface at sea in world war 1

At the start of the war the land and sea forces used the aircraft put at their disposal primarily for reconnaissance, and air fighting began as the exchange of shots from small arms between enemy airmen meeting one another in the course of reconnoitering. Fighter aircraft armed with machine guns, however, made their appearance in 1915. Tactical bombing and the bombing of enemy air bases were also gradually introduced at this time. Contact patrolling, with aircraft giving immediate support to infantry, was developed in 1916.

Explanation:

there is an explationation of this on a site called crash   course world history 1