“Employee,” as used in this part, does not include any of the following:

1. (a) A person engaged in household domestic service.
2. (b) A person employed under circumstances in which his wages are incidental to professional training and where the employer is exempt from taxation under subdivision (b) of Section 4 of Article XIII of the California Constitution.
3. (c) A person employed incidental to training for, or in furtherance of, a religious vocation and where the employer is exempt from taxation under subdivision (f) of Section 3 of Article XIII of the California Constitution.