In the given options, the sentence "She could feel her heart bootin" is not a complete sentence as it lacks the ending, making it grammatically incorrect.
The correct revision that uses the most precise language for the style of writing is option A: "Her heart kept pounding in her chest."
This revision is more precise and clear in describing the sensation the character is experiencing. It conveys a sense of palpable and intense emotion, which fits well with the style of writing that aims to portray the character's heightened feelings and inner turmoil.