//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

char answer;
console.writeline("choos your answer(a,b,c or d)");
answer=(char)(console.write());
if(answer=='c')
                  console.writeline("true");
if(answer=='a')||(answer=='b')||(answer=='d')
                  console.writeline("try again");
if((answer!='a')&&(answer!='b')&&(answer!='c')&&(answer!='d'))
                  console.write("try again");