As the kinetic energy of the particle continuously increases, means its velocity continuously increases in-turn it means it is accelerating. It can only happen if there is a positive component of the resultant force along the velocity. Now for it to happen the resultant force on the particle must be at an angle less than 90° all the time. So, option B is right.

Option A is only a part of option B which deals when angle is 0° and it is not a necessary condition.

Incase of option c as the direction of velocity is not given it is not true.

Whereas the option D is correct because the magnitude of v increases continuously hence the magnitude of linear momentum (mv) also increases continuously.