State whether the following statement is TRUE / FALSE.

A minimal $$DFA$$ that is equivalent to an $$NFDA$$ with $$n$$ modes has always 2ⁿ states

State whether the following statement is TRUE / FALSE.

All subjects of regular sets are regular.

State whether the following statement is TRUE / FALSE.

The intersection of two $$CFL's$$ is also $$CFL.$$

State whether the following statement is TRUE / FALSE. The problem is to whether a Turing Machine M accepts input $$w$$ is un-decidable.