Filtration is a mechanical solid-liquid separation operation in which a slurry or suspension is passed through a porous filtering medium (cloth, membrane, or bed) that retains insoluble suspended solid particles while allowing the clarified liquid (filtrate) to pass through.

Correct equipment-principle matches:

• Hammer mill: Operates via high-speed Impact of swinging hammers -> (II)
• Cyclone separator: Separates dust and flour particles using vortex Centrifugal force -> (IV)
• Spiral separator: Separates round seeds from flat/irregular seeds based on Grain shape rolling velocity -> (I)
• Indented cylinder separator: Separates grains based on Grain size (specifically length) -> (III)

Working principle of the spiral gravity separator:
(A) True: A spiral separator operates stationary without power, utilizing gravitational and centrifugal forces to separate round/spherical seeds (such as mustard, rape, vetch, and soybean) from oblong, flat, or irregularly shaped wheat and oat kernels.
(R) True: The operating mechanism is based precisely on seed roundness/sphericity. As seeds slide down the helical flights, spherical grains roll faster and gather sufficient centrifugal velocity to fly over the outer rim into an outer discharge flight, whereas flat/elongated grains stay close to the inner core flight.
Since (R) directly explains the physical mechanism governing the operational application stated in (A), option 1 is the correct answer.