How many code symbols can be formed using 3 out of 7 letters of A, B, C, D, E, F, G if the letters:a) are not repeated?b) can be repeated?c) are not repeated but must begin with D?d) are not repeated but must begin with DE?For each part, give the answer using permutation notation, factorial notation, or other operations. Then evaluate.E. 1.6P2G. 75F. 6!H. 7³There are 30 possible code symbols.(Simplify your answer.)d) What is the answer using the proper notation?A. 77C. 5!E. 1.6P2G. 75B. 6!D. 7!F. 7³H.1.1.5P1There are 5 possible code symbols.(Simplify your answer.)