The correct answer is A. periscope.
A periscope is an instrument used to see above or around obstacles. It is often used by submarines to see the surface of the water while they are submerged. Periscopes work by reflecting light through two mirrors. The first mirror reflects the light from the object being viewed up to the second mirror. The second mirror then reflects the light back down to the viewer. This allows the viewer to see the object even though they are below the surface of the water.
A telescope is an optical instrument that makes distant objects appear closer. It does this by using lenses to collect and focus light from the object. Telescopes are often used for astronomy, but they can also be used for other purposes, such as bird watching or sports viewing.
A kaleidoscope is an optical instrument that produces an ever-changing pattern of colors and shapes. It is made up of three mirrors that reflect light from colored objects. The mirrors are arranged so that the light is reflected back and forth, creating a pattern that changes as the kaleidoscope is moved.
A spectroscope is an instrument that separates light into its component colors. It does this by passing light through a prism, which bends the light according to its wavelength. The different colors of light are then separated into different bands. Spectroscopes are often used in astronomy and chemistry.