Answer:
D.
Explanation:
A sub-heading can be defined as an additional heading in a text. A sub-heading is a title given to sub-sections of the text. It comes after the main title or heading.
The guideline for writing a sub-heading is that never use all caps. A sub-heading should be written with the first letter in capital letter and the rest in small caps. The exception to this guideline is that nouns in sub-headings should be written in capital letters.
Therefore, option D is correct.
