Resolution of an optical imaging system will be reduced by I

Resolution of an optical imaging system will be reduced by Increasing light wavelength; Increasing aperture size of the system; Reducing area under modulation transfer function (MTF) of the system; Reducing focal length of the objective lens.

Solution

The resolution is high for larger area under the MTF.

The larger area under the MTF gives the good resolution.

So the resolution is reduced when the area under the MTF is reduced.

Therefore potion C is correct