Mary Ellen is struggling in her math class. She brainstorms three possible strategies to improve her grade. To help her decide, she identifies her criteria and weighs them as follows: High importance: must be easy to integrate into her daily schedule Medium importance: must be able to be quickly implemented Low importance: low cost She considers the three strategies: Hiring a tutor, which is expensive and can't begin for 2 weeks, but is very adaptable to Mary Ellen's schedule Purchasing study flashcards, which are inexpensive and can be used any time, but won't arrive in the mail for 2 days Attending her professor's help sessions, which is free and begins tomorrow, but takes place in the evening when Mary Ellen is at work According to her criteria, which strategy should Mary Ellen choose and why? a.) Hiring a tutor, because it will likely be the most effective. b.) Help sessions, because they will be the quickest to implement. c.) Study flashcards, because they meet all three of her criteria. d.) Hiring a tutor, because it meets her most important criteria