Final answer:
The best indicator of Muriel doing her push-ups correctly is her hand positioning, with palms placed slightly inside the shoulders for proper support and balance.
Step-by-step explanation:
The action that BEST shows Muriel doing her push-ups correctly is B. She places her palms slightly inside her shoulders. Correct push-up form requires that the hands be placed directly under the shoulders to provide proper support and balance, ensuring that the push-up targets the right muscle groups such as the chest, shoulders, and triceps. A curved back, as mentioned in option A, can lead to potential injury and does not engage the core effectively. Using only the arms for pushing up, as stated in option C, disregards the involvement of the core and lower body muscles in the exercise, which are important for maintaining proper stability. Lowering the chest to six inches above the floor, as in option D, ensures a full range of motion, but it is not the best indicator of correct form by itself without addressing hand placement.