Cryptography .NET, Avoiding Timing Attack

Question

I was browsing crackstation.net website and came across this code which was commented as following:

Compares two byte arrays in length-constant time.

Answer 1

this version goes on for the length of the input 'a'

    private static bool SlowEquals(byte[] a, byte[] b)
    {
        uint diff = (uint)a.Length ^ (uint)b.Length;
        byte[] c = new byte[] { 0 };
        for (int i = 0; i < a.Length; i++)
            diff |= (uint)(GetElem(a, i, c, 0) ^ GetElem(b, i, c, 0));
        return diff == 0;
    }

    private static byte GetElem(byte[] x, int i, byte[] c, int i0)
    {
        bool ok = (i < x.Length);
        return (ok ? x : c)[ok ? i : i0];
    }