It is best that you familiarize yourself with what a handover is. This is a type of communication that allows people to call another number without having to break the connection to do it. This means that calls will be very smooth and clear. There are two types of handovers: the hard handover and the soft handover. The main difference between the two is how they would allow the call to be made.
A hard handover would require the connection to be disconnected from the previous one before making a new call. A soft handover will require a new connection to the number that is being called first before connecting to the other number. LTE supports only hard handover at present time so the answer to this question is A.