Question

he is commonly referred to as the father of rock n roll due to his promotion of the style of music, and his introduction of the phrase rock and roll on mainstream radio in the early 1950s:
jim ladd
dick clark
alan ladd
alan freed

Explanation:

Alan Freed is credited with promoting rock - 'n' - roll and introducing the term on mainstream radio in the early 1950s.

Answer:

D. Alan Freed