How do you comment on if/else clauses in C (Objective-C, ...)?

comments.c

/*
 * Variant 1
 */

if (cond) {
    // Description of condition holding in if
    // code...
} else {
    // Description of condition holding in else
    // code...
}

/*
 * Variant 2
 */

// Description of condition holding in if
if (cond) {
    // code ...
// Description of condition holding in else
} else {
    // code ...
}

/*
 * Variant 3
 */

// Description of condition holding in if
if (cond) {
    // code ...
} else { // Description of condition holding in else
    // code ...
}

/*
 * Variant 4
 */

if (cond) { // Description of condition holding in if
    // code ...
} else { // Description of condition holding in else
    // code ...
}

/*
 * Variant 5?
 */