Determine whether the given statement is True or False. If it is true, give a brief reasoning as to why, otherwise give a counter-example

(a) (2 point) A language containing a regular language is regular.

(b) (2 point) The intersection of two non-regular languages is always non-regular.

(c) (2 point) The concatenation of a regular language with any non-regular language is regular.

(d) (2 point) The union of a non-regular language and a regular language cannot be non-regular.

(e) (2 point) L6 ={ (ab)^(n) : n 0 } is a non-regular language.