Q. Tots-R-Us operates only day care centre in an exclusive neighbourhood just outside of Washington, DC. Tot-R-Us is making a substantial economic profit, however owners know that new day care centres will soon learn of this highly profitable market and attempt to enter marker. Owners decide to begin spending immediately a rare large sum non advertising designed to decrease elasticity. Should they wait until new industries actually enter? Elucidate how advertising can be employed to allow Tots-R-Us to keep cost above average cost with encouraging entry