ANS:A - linearly with time.

If desiliconisation in a Basic Oxygen Furnace (BOF) were to occur linearly with time, it would mean that the rate of decrease in silicon content is directly proportional to the amount of time passed during the process. In other words, the silicon content would decrease by a constant amount for every unit of time. However, this scenario is not typically observed in chemical reactions like desiliconisation in a BOF. Instead, reactions in industrial processes often follow different kinetics, such as first-order reactions, second-order reactions, or more complex kinetics. In a first-order reaction, the rate of the reaction is proportional to the concentration of the reactant. As the concentration of the reactant decreases over time, the rate of reaction also decreases. This leads to an exponential decrease in the concentration of the reactant over time, not a linear decrease. Therefore, desiliconisation in a BOF is more likely to follow exponential kinetics rather than linear kinetics.