Direct Objects and Objects of Prepositions

Would someone please explain to me why my guess is wrong or right? I am confused about Direct Objects and Objects of a preposition. Thank you.

- Sweetie [k]

Even though the darkenng skies threatened rain, the band decided to play the concert.

A. Subject B. Verb C. Direct Object D. Object of a preposition

*My guess is C. Direct Object

We both thought that this novel was one of the finest books we ever read.

A. Subject B. Verb C. Direct Object D. Object of a preposition

*My guess is C. Direct Object

I plan to start writing before seven o'clock each morning.

A. Adjective B. Adverb C. Preposition D. Interjection

*My guess is C. Preposition

What I loved most about her was her laugh.

A. Noun B. Verb C. Adjective D. Adverb

*My guess is B. Verb

When it came to autumn, my thoughts often turned to the years I had spent quarterbacking my high school football team.

A. Subject B. Verb C. Direct Object D. Object of a preposition

*My guess is B. Verb