Consider the following method, which is intended to count th…

Consider the following method, which is intended to count the number of times the letter “A” appears in the string str. public static int countA(String str) { int count = 0;   while (str.length() > 0) { int pos = str.indexOf(“A”); if (pos >= 0) { count++; /* missing code */ } else { return count; } } return count; } Which of the following should be used to replace /* missing code */ so that method countA will work as intended?