The half-life of a substance is a characteristic property that describes how long it takes for half of the substance to undergo decay. This timeframe is independent of the initial amount of the substance.
So, if we started with a mass twice the size of the original sample, the half-life would not change. It would remain the same amount of time. Each half-life period would still see the substance's quantity decreasing by half; it would just be decreasing from a larger starting amount.
Therefore, the correct answer is:
O It would remain the same amount of time.
