What is the recommended best practices for font usage in email?

As part of their brand guidelines, NTO uses a custom brand font for all print marketing materials. NTO wants to use their custom brand font in email as well.

What is the recommended best practices for font usage in email?
A . Use a web-safe font for text that closely matches the brand’s custom font.
B . Build an email as one image, with all text saved in the brand font.
C . Edit an email’s HTML to list the custom brand font in the style tag’s font-family property.
D . Build an email using multiple images, with all text saved in the brand font.

Answer: A