Dr. Jeff gave George the following problem: "License plates in Mathlandia consist of six upper-case letters. For example, two possible Mathlandian license plates are $ABCDEF$ and $MMMATH.$ No two license plates are the same. How many possible Mathlandian license plates are there which contain at least four $M$'s?" George got the answer ((6 choose 4)*26^2) but Dr. Jeff told him this was the wrong answer!

(a) How did George arrive at his answer?

(b) Why is George's answer wrong? Should the correct answer be smaller or larger than George's answer (and why)?

(c) Write a solution to Dr. Jeff's problem, explaining in complete sentences what the correct answer to the problem should be and why.