Final answer:
Janice's presentation is aimed at instructing trainee nurses about guidelines for patient care, aligning with the purpose of an informative speech intended to educate and provide clear information.
Step-by-step explanation:
Janice, a nurse at a hospital, is preparing to address trainee nurses with a presentation on guidelines for patient care. The purpose of Janice's presentation is most aligned with option B - to instruct. This fits within the context of an informative speech, where the primary goal is to elucidate or demonstrate information clearly and effectively to the audience. In this case, the audience comprises trainee nurses who are expected to learn and apply the patient care guidelines presented by Janice. Her presentation is likely to be structured and educational, possibly incorporating various teaching aids such as media or demonstrations, ensuring that the content is comprehensible and applicable.