Nhận biết (M1)

The Timeline of African American Music, a website that traces the history of genres such as swing and bebop, is the result of decades of research by ethnomusicologist Portia K. Maultsby. She was not alone in her _________ Maureen Mahon and Fernando Orejuela, among other scholars, also contributed to the project.

Which choice completes the text so that it conforms to the conventions of Standard English?

• A.

  efforts, however,

• B.

  efforts, however:

• C.

  efforts however

• D.

  efforts; however,