Final answer:
The assassination of Airey Neave had a significant impact on Thatcher's IRA policy by revealing security weaknesses and solidifying her approach to countering perceived threats through increased support for military intervention, contrasting with diplomatic efforts.
Step-by-step explanation:
The assassination of Airey Neave was profoundly influential on Prime Minister Margaret Thatcher's stance towards the Irish Republican Army (IRA). Neave, who was Thatcher's close confidant and a prominent British politician, was killed by an Irish National Liberation Army (INLA) car bomb in 1979. This act highlighted the direct threat that paramilitary groups posed not just to public safety but also to the heart of the British government.
Neave's assassination underscored that the security measures in place were insufficient to protect even high-profile figures, revealing weaknesses in national security. It reinforced Thatcher's perception of the IRA and similar groups as not just ordinary criminals but significant threats to the state, leading to a hardened security approach. Thatcher's government subsequently increased security measures and took a more hardline approach to Northern Ireland, which included rejecting any form of negotiations with the IRA, and favoring strong military intervention when dealing with the group.
Thatcher's response after the assassination could be seen as aligning with option C from the student's question; it indeed led to increased support for military intervention against paramilitary groups in Northern Ireland. The tragic event, rather than leading to a search for diplomatic solutions, appeared to entrench adversarial positions, which would influence British policy in Northern Ireland for years to come.