Write Regular Expressions that will generate these languages over S = {a, b}. (10) Note about notation: Use parentheses, union operator, and star as needed. Its not necessary to use the concatenation operator its implied by contiguity of terms.

a) All strings containing the substring abba

b) All strings with an a preceding every b

c) All strings with an even number of characters, no fewer than 2.

d) All strings beginning with aa or ending with bb

e) All strings with no more than two bs in a row