Centurion with 1976 components - what model is it?

Black Centurion 23" center-to-top serial number MF00147 (seat tube 57cm center-to-center; top tube 56cm center-to-center; 40" wheelbase)

Can the list members please tell me:

a) What model designation is this circa ~1976 bicycle? b) Where does this model fit in the hierarchy of 1976-1977...