An Alexa Skill Builder Needs to Have Knowledge of the Previous

An Alexa Skill Builder needs to have knowledge of the previous prompt that was presented to the user in order to give context to the user's response. How can the Builder accomplish this?

A) Find the corresponding prompt using the list events feature
B) Store a reference to the prompt used as a session attribute
C) Call the Intent Request History API to identify which prompt was used.
D) Parse the context object from the skill request. Parse the context object from the skill request.