Final answer:
Analyzing data to determine appropriate nursing diagnoses is the critical thinking skill most relevant to formulating a nursing care plan.
Step-by-step explanation:
The critical thinking skill that is important to apply when formulating a nursing care plan is C. analyzing the data to determine appropriate nursing diagnoses. This involves a detailed process where a nurse must collect and evaluate information about a patient’s health status and needs. It includes making inferences, synthesizing information, and drawing conclusions based on the evidence gathered through patient history, assessments, and observations to create a comprehensive and effective care plan tailored to the patient’s unique health situation.