U. S. aid to Greece and Turkey to combat Communist guerilla forces was the first implementation of the: 1. Truman Doctrine
2. Roosevelt Corollary
3. Brezhnev Doctrine
4. Monroe Doctrine​

explanation: the line "to save the day, harry must get past a scary three-headed guard dog" from the summary best justifies the conclusion that harry potter and the sorcerer’s stone was influenced by ancient greek mythological literature. the three other choices had nothing to do with ancient greek literature - and the words "three-headed guard dog" are what makes that choice the correct answer.