Let L1 and L2 be two languages produced by grammars of a certain type. Let L be the language which is the concatenation of L1 and L2. We want to tell for various types of grammars that produce L1 and L2 what type is the concatenation L. Choose the triple (type1, type2, type3) so that when the grammar that produces the language L1 is of type1 and the grammar that produces the language L2 is of type2 , then the grammar that produces the concatenation language L may not be of type3.

Note: A linear grammar is a context-free grammar in which no production

body has more than one occurrence of one variable. For example, A 0B1 or A 001 could be productions of a linear grammar, but A BB or A A0B could not.

A linear language is a language that has at least one linear grammar.

a) (regular,regular,context-free)

b) (linear,regular,linear)

c) (regular, linear,regular)

d) (regular,regular,linear)

Plz explain me to learn more and what is the ans?