Two questions me 1.to create parallel structure in the sentence, which phrase would best replace the words "only landscapes"?

videos that have people in them are more interesting than only landscapes.

having videos with only landscapes

videos that have only landscapes

only landscape videos

to have only landscapes in videos

2.which revision of this sentence creates the best parallel structure?

to the cause you can write a check, collect donations, or signing the petition.

replace the word signing with the words to sign.

replace the word signing with the word sign.

replace the word write with the word writing.

replace the word collect with the word collecting.