The financial analyst at Company ABC gathered cost information for one element of the cost of its high performance widgets. In January, when ABC made 100 units, the cost was $8,000. In February when ABC made 140 units, the cost was $10,560. Which of the following is true?

a. The cost is a fixed cost.

b. The cost is a variable cost

c. The cost is a mixed cost.

d. The cost was a fixed cost in January and a variable cost in February.