The correct answer is A. Kaleidoscope.
A kaleidoscope is an optical instrument with two mirrors set at an angle to each other and a tube filled with loose colored materials. When the tube is turned, the materials reflect off the mirrors and create a constantly changing pattern.
A periscope is an instrument used to see over or around an obstacle. It consists of two mirrors, one at each end of a tube. The mirrors are angled so that light from an object above or below the observer is reflected into the observer’s eye.
A microscope is an instrument used to magnify small objects. It consists of a lens or lenses that focus light onto the object, and an eyepiece that magnifies the image formed by the lens.
A gyroscope is an instrument used to measure or maintain orientation and angular velocity. It consists of a wheel or disk mounted so that it can spin freely about an axis. The wheel is usually filled with a heavy liquid or gas, which helps to keep it stable.