Answer:
The complete code in Python language along with comments for explanation and output results are provided below.
Code with Explanation:
# the index variable will store the number of times "A" is entered
index = 0
while True:
# get the input from the user
letter = input('Please enter letter grades: ')
# if the user enters "enter" then break the loop
if letter == "":
break
# if user enters "A" then add it to the index
if letter == "A":
index = index + 1
# print the index variable when the loop is terminated
# the str command converts the numeric type into a string
print("Number of times A is entered: " + str(index))
Output:
Please enter letter grades: R
Please enter letter grades: A
Please enter letter grades: B
Please enter letter grades: L
Please enter letter grades: A
Please enter letter grades: A
Please enter letter grades: E
Please enter letter grades:
Number of times A is entered: 3
