Before an employer is liable for discrimination under the ADA, which of the following must be proven? Group of answer choices The employee must first prove that they are qualified to perform the job in question. The employer must first prove that the employee is not qualified to perform the job in question. The employee must first prove that they have an impairment that substantially limits one or more major life activities. The employer must first prove that the employee has an impairment that substantially limits one or more major life activities