Answer:
Naturally acquired active immunity
Explanation:
Naturally acquired active immunity occurs when an antigen comes naturally in the body and immune cells are produced against it which also generates memory against the pathogen. It can lead to disease or just cause a primary immune response in which host do not get sick.
Artificially acquired active immunity occurs when antigen is introduced from outside in the form of a vaccine or other substance. It can initiate primary response but do not cause disease.
So naturally acquired active immunity is the type of adaptive immunity which can cause subclinical infection.