In this Chapter, unless the context otherwise requires,

(20) "cab" means—

(i) a motorcab, or

(ii) a maxicab, or

(iii) any motor vehicle constructed or adapted to carry more than twelve passengers, excluding the driver, for hire or reward:

Provided that the maxicab referred to in sub-clause (ii) or motor vehicle referred to in subclause (iii) which is rented for use by an educational body imparting skill or knowledge or lessons on any subject or field, other than a commercial training or coaching centre, shall not be included within the meaning of cab;