What is the contrapositive for each statement? a. The common cold, flu, and other viral diseases occur when the immune system is weak. 1. If the common cold, flu, or other viral diseases occur, then the immune system is not weak. 2. If the common cold, flu, or other viral diseases do not occur, then the immune system is not weak. 3. If the common cold, flu, or other viral diseases do not occur, then the immune system is weak. b. If you subtract $750 for each dependent, then the computer will reject your return. 1. If the computer did not reject your income tax return, then you subtracted $750 for each dependent. 2. If you did not subtract $750 for each dependent, then the computer will not reject your return. 3. If the computer did not reject your income tax return, then you did not subtract $750 for each dependent