Gray fill-in-the-blank box in pdf exercise

[APEXCalculus]

Exercise 5 of 12.5 has a fill-in-the-blank answer that appears as a grey box in the pdf, an artifact of the WeBWorK code. Is there a way to re-code this so it is just a blank line, such as

_________ * N(s)?

[sean-fitzpatrick]

It looks like PreTeXt uses two style defaults: a fill-in-the-blank that appears in text is an underline, but if it appears in math mode, it's a shaded box. According to the guide, we can control this in the publication file:
Subsection 45.1.4: Fillin Options

I'll add this change to the pull request I have open.

By the way, in HTML, this is a sorting problem: Exercise 12.5.4.5

[APEXCalculus]

Sounds good. Thanks.