Question 8 (Mandatory) (1 point) If a firm's economic profit is $0, then it must be t TR equals TC. TR equals TFC. TR equals TVC. O TFC is zero. Question 9 (Mandatory) (1 point) If a household's income rises by 30%, its budget co O shift out parallel to the old one. pivot at the Y-intercept. shift in parallel to the old one. be unaffected