Classical Music: Who wrote the "Unfinished Symphony" (in B minor) ?

Questions

"I know I'm being used, that's okay man cause I like the abuse"?

"I, ohhhhhhh, I'm still _____"?

Although his early career was snuffed out in the same plane crash that killed Buddy Holly, this east L A kid had a memorable top ten hit about his girlfriend, Donna?

Although the fabulous Thunderbirds sang 'I Thank You' it was originally released by this soul duo in 1968.?

Although the Fireballs had some success with the record "Torquay" when they teamed up with Jimmy Gilmer, this record stayed at number one for an entire year?