Bill Board leaves his $50,000-a-year job as a marketing manager for a small retail business and starts his own outdoor sign/advertising company. In the first year of operation his new business earned an accounting profit of $70,000. Based on all of this data, aneconomistwould advise Bill to

return to his old job because his economic profit is smaller than his accounting profit

return to his old job because his economic profit is less than his old salary

stay with his new firm because his economic profit is positive

stay with his new firm because accounting profit is positive