Which of the following must be true if at the 10th unit of output, marginal cost is $130 and ATC is $150? 2 ATC of producing the 9th unit is higher than $150 MC of producing the 9th unit is higher than $130 AVC of producing the 10th unit is equal to $20 ATC of producing the 9th unit is less than $150 AVC of producing the 10th unit is higher than $150