please answer these questions right. Read very carefully before answering. Answer each part

$1.$ Write BNF grammar for the if$/$else conditional statement of C$.$ Assume the following for this:

You already have defined for you and and nonterminals. You SHOULD NOT define them or redefine them, just use them as nonterminals.

Block is NOT the same as a statement $($different books take different take on this$)-$ block is $\{\}$ with variables and statements inside. Do not use the extended BNF notation.

$2.$ Design a regular language where every sentence has to start with any number of strings $10($any number is none or more$),$ then repeats $0101$ any number of times, then repeats $01$ at least once $($but could be more$).$ Use regular expression notation.

Clarification: alphabet is $\{0,1\}.$ 'string' is the same as a program in this context, but here the programs are written using the binary alphabet so strings here are binary; in regular expressions we use $*$ for any number, $+$ for one or more, $|$ for either and $()$ for grouping.

$3.$ For the above, how many different valid strings there are?

$4.$ For the above, how many valid strings are there if we restrict the total length to at most $10$ bits? Give your reasoning for this. Remember that if the strings are identical, even if they were derived in a different way, they are still the same strings.