Explanation:

• CTBT was negotiated at the Conference on Disarmament in Geneva and adopted by the United Nations General Assembly in 1996.
• The Treaty intends to ban all nuclear explosions - everywhere, by everyone. It was opened for signature in 1996 and since then 182 countries have signed the Treaty, most recently Ghana has ratified the treaty in 2011.
• A comprehensive test ban has been defined as a “zero yield” test ban that would prohibit supercritical hydro-nuclear tests but not sub-critical hydrodynamic nuclear tests.
• As of August 2011, 36 of these States have ratified the Treaty. Eight States still need to do so: China, North Korea, Egypt, India, Iran, Israel, Pakistan and the United States.
• India, North Korea and Pakistan have not yet signed the Treaty. Hence all statements are correct.