The correct option is "1 only" because a deadlock between the Lok Sabha and Rajya Sabha can only be resolved through a joint sitting of Parliament concerning ordinary legislation. This is stipulated under Article 108 of the Indian Constitution, allowing for a joint sitting when both houses disagree on a bill. In contrast, Money Bills (Article 110) must originate in the Lok Sabha, and a Constitution Amendment Bill (Article 368) requires passage from both houses, but joint sittings are not applicable for these, reflecting the distinct procedural rules governing different types of legislation.