23.Hexadecimal numbers are made using the sixteen digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. They are denoted by the subscript 16. For example, 9A2D16 and BC5416 are hexadecimal numbers. Note for the questions below: a number cannot begin with a zero, but a string can begin with a zero. a.How many hexadecimal numbers begin with one of the digits 4 through D, end with one of the digits 2 through E, and are 6 digits long?b. How many stringsof hexadecimal digits consist of from two through five digits? (2 or 3 or 4 or 5)c. How many strings of four hexadecimal digits have no repeated digits?d. How many strings of four hexadecimal digits have repeated digits? (e. g., A232, 4443, ABBA) e. What is the probability that a randomly chosen string of four hexadecimal digits has repeated digits?