Final answer:
The Beach Boys were formed by Brian Wilson and his relatives and friend. Brian Wilson was instrumental to the band's sound and success in the pop music scene.
Step-by-step explanation:
The Beach Boys, a seminal American rock band, were formed in the early 1960s by Brian Wilson, his brothers Dennis and Carl Wilson, their cousin Mike Love, and friend Al Jardine.
Therefore, the correct answer to the question is a) Brian Wilson. The Beach Boys are known for their harmonious sound and innovative recordings, which played a significant role in the evolution of pop music during the 20th century.