A driver is unable to identify most of the numbers contained in the Ishihara's color blindness charts and cannot distinguish traffic signal color cards in red, green and amber. The examiner should:
a) Disqualify the driver because he is colorblind.
b) Refer the driver to an Ophthalmologist for further evaluation.
c) Complete the medical examination and refer the driver for a vision exemption.
d) Accompany the driver to traffic signal to confirm they can differentiate colors.