Which relation is a function?

a.
{(1, 2); (2, 3); (3, 4); (2, 5)}

b.
{(1, 2); (2, 3); (3, 4); (4, 5)}

c.
{(1, 2); (1, 3); (1, 4); (1, 5)}

d.
{(1, 2); (3, 2); (3, 3); (4, 2)}

Select the correct answer from each drop-down menu. the table shows the annual sales revenue for different types of automobiles from three automobile manufacturers. sales revenue (millions of dollars) suv sedan truck marginal total b & b motors 22 15 9 46 pluto cars 25 27 10 62 panther motors 26 34 12 72 marginal total 73 76 31 180 the company with the highest percentage of sales revenue from sedans is . of the annual sales revenue from suvs, the relative frequency of pluto cars is .