House Rent Allowance u/s 10(13A) with Rule 2A

Minimum of the following would be exempt u/s 10(13A) with Rule 2A :-

(1) House Rent Allowance Actually Received
(2) Rent paid - 10% of salary
(3) 40% or  50% of salary(50% for Mumbai, Kolkata, Delhi, Chennai. and 40% for others)

NOTE - Salary for this purpose:-
              Basic Salary + Dearness Allowance(term of employment for retirement benefits) + commission on turnover.