Define the Unrestricted Grammar. Consider the unrestricted grammar with the given productions

S-->TDE, T-->ABCT |, AB-->BA, BA-->AB, CA-->AC,

CB-->BC, CD-->DC, CE-->Ea, BD-->Db, A-->a, D-->, E-->.

a) Describe the language generated by this grammar.

b) Find a single production that could be substituted for BD-->Db so that

the resulting language would be

{xaⁿ | n 0, |x|=2n, and Na(x)=Nb(x)=n}