B.—Income  from house property 
[Unrealised  rent. 
4.  For the purposes of the Explanation below sub-section (1) of section  23, the amount of rent which the owner cannot realise shall be equal  to the amount of rent payable but not paid by a tenant of the assessee and so  proved to be lost and irrecoverable where,— 
(a)  the tenancy is bona fide; 
(b)  the defaulting tenant has vacated, or steps have been taken to compel him to  vacate the property; 
(c)  the defaulting tenant is not in occupation of any other property of the  assessee; 
(d)  the assessee has taken all reasonable steps to institute legal proceedings for  the recovery of the unpaid rent or satisfies the Assessing Officer that legal  proceedings would be useless.]  |