Final answer:
George Harrison is the only Beatle on the track 'Within You Without You,' and the laughter at the end is due to a humorous incident during recording.
Step-by-step explanation:
The song "Within You Without You" features George Harrison as the only Beatle heard on this track. The laughter at the end of the song is due to a funny incident during recording, which makes option a) the correct answer. "Within You Without You" is a track from the Beatles' iconic album Sgt. Pepper's Lonely Hearts Club Band, released in 1967.
The song is known for its fusion of Western rock with Indian classical music, featuring instruments like the sitar, tabla, and tampura. The inclusion of laughter at the end of a track with serious lyrical content serves as a contrasting element, potentially highlighting the universality of human emotions or perhaps as a light-hearted closure to a profound track.