A student is taking a multiple-choice exam in which each question has two choices. Assuming that she has no knowledge of the correct answers to any of the questions, she has decided on a strategy in which she will place two balls (marked A and B) into a box. She randomly selects one ball for each question and replaces the ball in the box. The marking on the ball will determine her answer to the question. There are seven multiple-choice questions on the exam. Complete parts (a) through (d) below a. What is the probability that she will get seven questions correct? (Round to four decimal places as needed.) b. What is the probability that she will get at least six questions correct? (Round to four decimal places as needed)