What is missing from this summary? So, Opal found a dog, and the dog helped her to make friends. O A. The characters O B. The ending ОО O C. The problem O D. The solution​

Which choice is a major detail from paragraph two? a) the great wall is a large network of several walls and towers. b) the great wall looks like a long wall snaking its way across china. c) the great wall was constructed over hundreds of years beginning in 221 b. c. d) the great wall construction encouraged several independent kingdoms to unite.