The correct answer is (c). In case of differences between the two houses of the Parliament on an ordinary bill, the same is resolved by convening a joint sitting of the two houses.
A joint sitting is a meeting of both houses of Parliament, the Lok Sabha and the Rajya Sabha, to resolve a deadlock on a bill. The Speaker of the Lok Sabha presides over the joint sitting. If the bill is passed by a majority of the total number of members of both houses present and voting, it is deemed to have been passed by both houses.
The other options are incorrect. The President does not have the power to resolve differences between the two houses of Parliament on an ordinary bill. The Speaker of the Lok Sabha can only preside over a joint sitting of the two houses, and does not have the power to resolve differences between the two houses. A joint committee of the two houses is a committee of members from both houses that is appointed to resolve differences between the two houses on a bill. However, a joint committee is only appointed if the two houses are unable to resolve their differences through negotiations.