C - OR in IF statements not working has I want

I've started learning C really recently in school, and I'm having a problem which I can't see where's the mistake. I'm currently learning functions, and I have to develop a program that calculates the area of some geometric shapes with multiple functions. That's not going so well, but the problem I have is related with OR in IF statements. I'm trying to make the user select specific charecters, otherwise it will show "Invalid option, try again". The problem is that even if the users chooses the correct chars, the "warning" will show. Sorry for bad english.

        int menu()
        {
            char opc;

        do
            {
                printf("Areas\n");
                printf("\nTriangle (nr):  \t\t\tRectangle (nr):  \n");
                printf("\nCircle (nr):  \t\t\t\tSquare (nr):  ");
                printf("\n\n\t\tOPIONS");
                printf("\n\n\t(T)riangle\n\t(R)ectangle\n\t(S)quare\n\t(C)ircle\n\t(E)nd\n\n");
                scanf(" %c", &opc);
                if((opc!='t') || (opc != 'c') || (opc != 'r') || (opc != 's') || (opc !='e'))
                   {
                        printf("\nInvalid option, try again\n");
                   }
            }
        while(opc!='e');
            return opc;

       }