A graph plotted between the concentration of reactant, consumed at any time (x) and time ‘t’ is found to be a straight line passing through the origin. The reaction is of:

Zero-order

If a graph plotted between the concentration of reactant consumed and time is a straight line passing through the origin, it indicates a zero-order reaction.
In a zero-order reaction, the rate of the reaction is independent of the concentration of the reactant. The concentration decreases at a constant rate over time, resulting in a linear decrease when plotted against time.
Therefore, the correct answer is option (2) Zero-order.