How does an acoustical-seismic device detect an intruder?

A.
Change in vibration

B.
Change in magnetic field

C.
Change in microwaves within room

D.
Break of foil strip in window

Explanation:
Acoustical-seismic device detect vibration changes within a given area
and can easily cause false alarms if they are very sensitive. A proximity device
monitors an electronic field, and a electromechanical detection detects a break in
foil strips.