A user calls the help desk to report about their smartphone not being able to make any phone calls. The user admits that the smartphone can still send/receive email, browse all websites, and utilize all Internet-capable applications. Which of the following issues is MOST likely affecting the smartphone?
A. Wi-Fi is turned off; the cellular antenna is turned on.
B. The cellular antenna is turned off; Wi-Fi is still on.
C. The user forgot to turn off Bluetooth before trying to make a call.
D. The user has 4G capability turned off, and is only on 2G.