Z97-A has M.2 Socket 3, , with M Key, type 2260/2280 storage devices support (PCIE mode).
I believe the AC Wireless/Bluetooth combo cards are keyed for A and E.
See table in this link for key.
http://arstechnica.com/gadgets/2015/02/understanding-m-2-the-interface-that-will-speed-up-your-next-ssd/