How to check whether substring exists in string using strstr() function in C

This must be a simple problem about char data type and pointers.

void main() {

    const char* a;
    char character = 65;
    a = &character;

    printf("%c n", character); // PRINTS 'A' AS EXPECTED

    if (strstr("ABC", a)) { 
        printf("found n");
    }
    else {
        printf("not foundn"); // goes into else
    }
}

I don’t understand why it doesn’t go into first if statement.