Sony Was a Pioneer in the Portable Music Market Segment

Sony was a pioneer in the portable music market segment. Sony's Walkman was an innovative product which created a new category altogether and made Sony a technological leader. This gave the company an edge over other consumer electronics brands that introduced portable music players for a very long time. In this example, Sony had the:

A) vertical integration advantage.
B) purchasing power parity advantage.
C) free-rider advantage.
D) first-mover advantage.