Number 3, as below:
Subsidised interest for housing, education or car loan is fully exempted from tax if the total amount of loan taken in aggregate does not exceed RM300,000. If the total amount of loan exceeds RM300,000, the amount of subsidized interest to be exempted from tax is limited in accordance with the following formula:

An amount limited to a maximum of RM10,000 is deductible for each basis year for a period of three consecutive years of assessment beginning from the date in which the interest is first expended.
Conditions for eligibility:
(i) an individual who is a citizen and resident;
(ii) the purchase of the residential property is limited to one unit only;
(iii) the Sale and Purchase Agreement has been executed from 10 March 2009 to 31 December 2010; and
(iv) that residential property must not be rented out
Where:
(a) 2 or more individuals are each entitled to claim deduction in respect of the same residential property; and
(b) the total amount of interest expended by those individuals exceed

This is official guide from LHDN:

(a) 2 or more individuals are each entitled to claim deduction in respect of the same residential property; and
(b) the total amount of interest expended by those individuals exceed the amount of deduction allowable for that relevant year, There shall be allowed to each of those individuals for that relevant year an amount to be determined in accordance with the following formula: A x B/C
Where;
A = total amount of deduction allowed for that relevant year;
B = total interest expended in the basis year for the relevant year by that individual; and
C = total interest expended in the basis year for that relevant year by all such individuals.

Honestly if more than 300k, I'm not sure still can claim or not? Either leave for some expert to advice or you may call LHDN for details.

Just my advice, based on my experience, for those who claim this rebate, most of them will get LHDN to ask for submit the supporting document. So be sure before you submit.