In a frequency-hopping spread spectrum (FHSS) system that uses 10 frequencies across a 12 megahertz (MHz) frequency band, what happens if narrowband interference occurs at only one of the 10 frequencies?
a) The spread spectrum signal is lost completely.
b) The system switches to a different frequency band.
c) The interference causes the system to shut down temporarily.
d) The spread spectrum signal remains intact. Instead of being lost, the data on the interfered frequency is retransmitted on one of the other nine frequencies.