The Rowlatt Act aimed at

The correct answer is B. The Rowlatt Act of March 1919, formally the Anarchical and Revolutionary Crimes Act, carried the wartime emergency powers of the Defence of India Act into peacetime. It allowed the executive to detain persons without trial for up to two years and let special benches of High Courts try political offences without juries, using summary procedures and a lower evidentiary bar.

• A is wrong. Compulsory support to war efforts came under the Defence of India Act, 1915 and its rules, not the Rowlatt Act.
• C is wrong. The Khilafat Movement (1919-24) was a Muslim-led agitation over the Ottoman caliphate. The Rowlatt Act was never aimed at it, though the two agitations overlapped and later merged into Gandhi's Non-Cooperation campaign.
• D is wrong. Press control came through the Indian Press Act, 1910 and, later, the Press (Emergency Powers) Act, 1931, not Rowlatt.

Core concept: preventive detention and suspension of ordinary criminal procedure in the name of security. The Act's passage triggered Gandhi's satyagraha call and the Jallianwala Bagh massacre (April 1919). It is a strong Mains anchor for civil liberties and colonial governance.

Trap: candidates pick D because the Act is remembered as a gag law. Its core features were detention without trial and special courts; press laws were separate statutes.