A refinement to the basic Waterfall Model that states that software
should be developed in increments of functional capability is called:

A.
Functional development

B.
Incremental development

C.
Functional refinement

D.
Incremental refinement

Explanation:
The advantages of incremental development include the ease of
testing increments of functional capability and the opportunity to
incorporate user experience into a successively refined product.
The other answers are distracters.