A tempo is used after a change of tempo, to indicate that the person playing the instrument or singing should return to the original or main tempo. B is correct.
BPM stands for beats per minute and it is used to measure the tempo of a piece of music (tempo <em>refers to the pace or speed of a piece</em>.) So, a tempo marking of presto indicates a very quick BPM.
The measure of an inscribed angle is half the measure of the intercepted arc. That is, m∠ABC=12m∠AOC. This leads to the corollary that in a circle any two inscribed angles with the same intercepted arcs are congruent.
