The correct answer to this open question is the following.
Unfortunately, there are no more references or context attached. However, we can comment on the following terms.
Textual aids are educational instruments that are used in classrooms and
workplaces and serve to increase the teaching tools to improve the quality of education. Some of these texts serve to simplify texts in the classroom. Images are commonly known to be an important part of these texts because they add visual content that allows students to better understand the lessons and make them more fun.
One good example of textual aids is commonly known as cause and effect diagram and serves to identify the consequences of the decisions made.
I think the answer is either
A. Why does Harry seem sad at the end of the passage.
or
D. Where will jack and Harry find work after the professor leaves?
The suffix “-able”
Suffix is an affix mostly paced in the end or after a word’s original root. It takes on many cases to describe a word either in verb or adjective. For example running notice that –ning is the suffix in this word while beautifully, take the root word of beautiful and the suffix –ly as we break down the words.