Answer:
A & D
Step-by-step explanation:
Wifi or IEEE 802.11a/n/g is a wireless network medium used for communication between devices in a network (or the internet). It is used to transfer video, text, graphic, audio and all other types of files.
Cellular is a mobile networking technology used to make wireless communication over a large area of land called cell, between devices in a network or a remote network.
Both cellular and wifi connections are used to synchronize smartphones to online accounts and allows for data backup and retrieval.