The second one "mice's" because it's talking about the mice favorite spot also mice means one
Starting on a project at the last minute can increase anxiety<span />
The following words should be capitalized: B) A, D) Sound, and C) Thunder.
When it comes to the names of novels an such, all words (except for prepositions and linking verbs) should be capitalized. For example - The Lord of the Rings, A Sound of Thunder, etc.
The source could be wrong or biased or both.
