What note receives one fourth beat in alla breve

Short answer-half note.

In common time the quarter note equals one beat, and there are four quarter notes in a measure.

Songs in alla breve contain two beats per measure, with the half note equaling one beat. That means that the time signature of the alla breve is represented as 2/2 (not 4/4 as common time is).

B. is the correct answer.

Cthe lindisfarne gospels