Answer: 8.1 msec.
Explanation:
If we are told that we have a transmission link of sending 10 Mbits in one second, setting up a direct proportion, we can find out how much time is needed to send 4096 bits along the same channel, as follows:
10⁶ bits = 1 sec
4096 bits = x ⇒ x = 4096 bits. 1 sec / 10⁶ bits = 4.1 msec.
As we have 4 msec of latency between sender and the receiver, we need to add these 4 msec to the transit time, so we have a total message transmission time of 8.1 msec.