A. is the correct answer; "Several dirty footprints" makes sense. All the other verbs do not agree with their subjects.
Whats YOur Question About it though?
I have had many dreams that have predicted the future like the matrix with deja vu. They do have special meanings. Like I said previously if they can predict the future then they can obviously have deeper meanings.
1. The whole class laughed loudly at the story.
complete subject: the whole class
complete predicate: laughed loudly at the story
2. The whole class laughed loudly at the story.
simple subject: class
simple predicate: laughed
3. Twelve hours passed without a word from any of the group.
simple subject: hours
simple predicate: passed
4. The workmen repaired the dam.
complete subject: the workmen
complete predicate: repaired the dam
