Write the next sentence in the following story.

How to socialize pet rats
Minimize her stress.
Rats can be stressed by new environments. Minimizing her stress the first few days you have her can make it easier to socialize her.

OPTIONS:
a). Find a spare space where she can roam on her own. This could include her off-leash, her cage, or a park bench.
b). Give her some space at first, though, as her environment will vary from place to place. Keep your dog loose in the room she frequents so she won't have anxiety when she must be around new people.
c). The first few days you have your rat train is important since she can handle new environments. Expose her to sights, smells, and sounds, such as books and radios.
d). The following can help your rat get used to her environment : Preparing her nesting box before she arrives using the type of food and bedding she's used to before slowly introducing new products allowing her to settle by not handling her. Start socializing as soon as possible.. The answer should be
d).