most of americans don't object---- by their first name.A.to

选B.
1.object to 意思为反对,在这个词组中to是介词,所以后面要跟名词或v-ing.
2.这句话的主语是Most of Americans,和call之间构成动宾关系（即被动关系）,因为词组是call most of Americans by their first name,所以要用object to being called.