Aparagraph in a narrative that sustains interest or makes a transition is called a paragraph.

a. topical

b. functional

c. narrative

d. sustaining

Sustaining paragraph is used in a narrative which sustain interest. This is a paragraph that does not change the tone or theme as it is just constant. The interest is just the same and no rising action is made. It is common in general knowledge and informations that are known to all.