20 points! 1. the mason-dixon line, which is perhaps the most famous border ever established by surveying methods, has been designated a national historic landmark. which of the following is the main clause in the sentence? a. the mason-dixon line b. has been designated a national historic landmark c. the mason-dixon line has been designated a national historic landmark d. which is perhaps the most famous border ever established by surveying methods 2. the mason-dixon line, which is perhaps the most famous border ever established by surveying methods, has been designated a national historic landmark. which of the following is the adjective clause in the sentence? a. the mason-dixon line b. which is perhaps the most famous border ever established c. by surveying methods d. a national historic landmark 3. the mason-dixon line, which is perhaps the most famous border ever established by surveying methods, has been designated a national historic landmark. which of the following are the two participles in the sentence? a. "mason-dixon line" and "national historic landmark" b. "is perhaps" and "established by surveying methods" c. "the most famous border" and "surveying methods" d. "established" and "has been designated"