No exchange option in gmail "add account" drop down I cannot see exchange account option on gmail add account. Gmail version 5.0.1. How to rectify this?
Gmail 5.0 added support for Exchange accounts, but it requires an additional APK (Exchange Services) which you can't get from the Play store unless you already have it.  As one of the other answers indicates it seems to just be with Nexus devices at the moment (maybe some newer Lollipop ROMs do for other devices, not sure).

However, you can sideload it!  I just did from APK Mirror (using this version) and after fully closing and restarting Gmail I had the option to add an Exchange account.