In the context of medical examinations and inquiries in the selection process, which of the following is true of the Americans with Disabilities Act $($ADA$)?$

Select one:

a$.$ The ADA authorizes the use of pre$-$employment medical exams before a job has been conditionally offered to a job applicant.

b$.$ Hiring an individual because of drug use for treatment, medical, or nonmedical purposes violates the ADA.

c$.$ The ADA prohibits a company from asking job applicants any question related to current or past medical history until a conditional job offer has been made.

d$.$ Pre$-$employment drug tests are considered to be medical exams under the ADA. $*$