Merge Method Loop Assertion

The following merge method is intended to combine two sorted arrays, v and w, into a single sorted array named result.

/** Merges two sorted arrays v and w into a new sorted array result.
* Precondition:
* - v is an array of int sorted in increasing order
* - w is an array of int sorted in increasing order
* - N is the number of elements in array v
* - M is the number of elements in array w
* - v[0]..v[N-1] and w[0]..w[M-1] are initialized with integers.
* - v[0] < v[1] < ... < v[N-1] and w[0] < w[1] < ... < w[M-1]. */

public static int[] merge(int[] v, int[] w, int N, int M) {
    int[] result = new int[N + M];
    int vIndex = 0, wIndex = 0, rIndex = 0;
    while (vIndex < N && wIndex < M) {
        if (v[vIndex] <= w[wIndex]) {
            result[rIndex++] = v[vIndex++];
        } else {
            result[rIndex++] = w[wIndex++];
        }
    }
    while (vIndex < N) {
        result[rIndex++] = v[vIndex++];
    }
    while (wIndex < M) {
        result[rIndex++] = w[wIndex++];
    }
    return result;
}

Which of the following assertions is true at the end of each iteration of the first while loop?