Under the ADA an individual $\_\_\_\_\_\_\_.$

a$.$ is presumed to be disabled unless an employer, or prospective employer can prove otherwise

b$.$ is disabled only if the individual has an impairment that substantially limits all major life activities

c$.$ is disabled if the individual has an impairment that substantially limits one or more of the major life activities

d$.$ is disabled if she suffers from any medically recognized disorder