In Many Places 24 V AC Has Been Popular as a Power

Multiple Choice

In many places 24 V AC has been popular as a power source but now 12 V and 24 V DC is increasing in popularity because

A) There is more energy in DC.
B) It is easier to back-up DC with battery.
C) There is less power loss in cables with DC.
D) There is less risk for surge with DC.