please help with questions True or False

14. If both generate the same tax revenue, a unit tax induces greater quantity distortion than an ad valorem tax(-' 15. Market power always reduces overall welfare. 6' 16. Mark up is the amount charged above marginal cost. 6' 17. When a firm uses quantity discrimination [block pricing), it is the high quantity purchasers who payr a higher price per unitk' 18. A Nash Equilibrium occurs when players do not have reason to deviate given the action of their opponent.