Read the passage.

This jungle presented a new challenge for Enid. Sure, she had been on many safaris before. Yes, she had spent hours unsupervised with large animals in her position as a head zookeeper. Her resume listed her qualifications. But something felt different. This day would likely not be smooth sailing. She would have to rely on her finely tuned set of survival skills, but she knew she’d succeed.

Which stylistic element most contributes to the informal tone of this passage?

the reference to her qualifications in “Her resume”
the use of short words and commas at the beginning of sentences
the alliteration in “set,” “survival,” and “skills”
the alternation of short and long sentences in the passage