Answer:
contact button
Step-by-step explanation:
When designing a website for users the main aim of the website is to get your site visitors to be engaged with what your website is all about and what product or service you offer to them. hence including a contact button which also be a called " call to action" button will help make your website more engaging and interactive.
including a navigation button will only direct your site visitor around the site which he or she can do without if the site is properly designed when creating it. including pictures and FAQ as a web page in your website is good but including a button for it is not necessary.