Athletes who are removed from play because of a possible concussion should return to play only after they are back to their regular school activities.

Which of the following sentences requires a colon to be correct? a. in his vacation suitcase, jonathan packed two pairs of pants, four shirts, his swimsuit, and his favorite pajamas. b. when she decided to write a letter, she grabbed her pen, paper, stamps, and address book. c. the new dessert recipe called for equal parts of sugar, cream, peanut butter, and crushed pecans. d. she gathered all of her ingredients to make a smoothie strawberries, blueberries, bananas, and yogurt.