Which of the following statements is correct?

a) The short run is a time period of one year or less.

b)) The short run is a period of time during which the quantities of all inputs can be varied, but technology is held constant.

c) The short run is a period of time during which the quantity of at least one input is fixed and the quantities of the other inputs can be varied.

d)) The long run is a period of time during which the quantities of all factor inputs are fixed.The time period separating the short run from the long run is at least 3 months.