Dropdowns
Recommendation: Avoid the use of dropdowns in navigation.
Why?
With the rise of mobile navigation, dropdown/hover navigation might not be the best choice. Dropdown menus tend to operate on hover only. Unlike web interfaces, mobile devices do not have the capability for hovering, which leads to problems for mobile users trying to access sub-menus.
Hamburger menus tend to be a safer option when dealing with responsive websites for mobile devices. Additionally, activating/hiding sub-menus on-click is a better way to make sure users can access the content they are looking for.