Final answer:
Lisa is gaining work experience option (a) by volunteering at the animal shelter without being paid.
Step-by-step explanation:
Lisa is gaining work experience option (a) by offering to help at the animal shelter without being paid. This allows her to learn more about the veterinary field and gain practical skills that can be valuable in her future career as a vet. By volunteering at the animal shelter, she can also demonstrate her commitment and passion for animals, which can be advantageous when applying to veterinary school or seeking job opportunities in the future.
This hands-on experience can be valuable in helping her decide if pursuing a career as a vet is the right path for her, and it can enhance her qualifications when applying for future opportunities in the veterinary field.