Question

Objects at the surface of water can be viewed from a submarine under water by using this instrument.
a) Stethescope
b) Periscope
c) Kaleidoscope
d) Telescope

Answer 1

Objects at the surface of water can be viewed from a submarine under water by using periscope.

Answer 2

Periscope
-----------
Objects at the surface of water can be viewed from a submarine under water by using by periscope