Consider the following rucursive descent parser: void a() { if( next_token == 'a' ) { lex(); if( next_token == 'a') { lex(); a(); lex(); c(); } else error(); } else if(next_token == 'b') { lex(); b(); lex(); c(); } else error(); }void b() { if( next_token == 'a' ) { lex(); if( next_token == 'b' ) { lex(); b(); } else error(); } else if ( next_token ! = 'b' ) { error(); }}void c() { if( next_token == 'c' ) { lex(); if( next_token == 'a' ) { lex(); if( next_token ! = 'b' ) { error(); } } else error(); } else error(); }which of the following strings will parse without an error? a. aabbcabcabb. aacabbbcabc. cab