This task involves annotating the answer type to a given question that involve some kind of complex reasoning (including numerical reasoning). Note that the questions require looking at more than one part of the passage to answer. There are 3 possible answer types (i) spans, (ii) numbers and (iii) dates. If the answer can be found in the passage, label it as "span". If the answer is a number, label as "number". Similarly, label "date" if you think the answer to the given question is a date.
One example: Passage: The outbreak of the Seven Years' War in Europe in 1756 resulted in renewed conflict between French and British forces in India. The Third Carnatic War spread beyond southern India and into Bengal where British forces captured the French settlement of Chandernagore in 1757. However, the war was decided in the south, where the British successfully defended Madras, and Sir Eyre Coote decisively defeated the French, commanded by Comte de Lally at the Battle of Wandiwash in 1760. After Wandiwash, the French capital of Pondicherry fell to the British in 1761. The war concluded with the signing of the Treaty of Paris in 1763, which returned Chandernagore and Pondichery to France, and allowed the French to have "factories" in India but forbade French traders from administering them. The French agreed to support British client governments, thus ending French ambitions of an Indian empire and making the British the dominant foreign power in India.
Question: Which french settlement did the British capture first, Chandernagore or Pondicherry?
Solution is here: span
Explanation: The answer "Chandernagore" is a word from the passage. So, the answer type is "span".

Now, solve this: Passage: In late 1920, the Persian Soviet Socialist Republic in Rasht was preparing to march on Tehran with "a guerrilla force of 1,500 Jangalis, Kurds, Armenians and Azerbaijanis", reinforced by the Bolsheviks' Red Army. This fact, along with various other disorders, mutinies and unrest in the country created "an acute political crisis in the capital." By 1921, the ruling Qajar dynasty of Persia had become corrupt and inefficient. The oil-rich nation was somewhat reliant on the nations of Britain and Russia for military and economic support. Civil wars earlier in the decade had threatened the government, and the only regular military force at the time was the Cossack Brigade. The Qajar shah in 1921 was Ahmad, who had been crowned at the age of eleven. He was considered to be a weak, incompetent ruler, especially after British, Russian and Ottoman occupations of Persia during World War I. In 1911, when the capital city, Tehran, had been seized by the Russians, armed Bakhtiaris tribemen, rather than Iranian regular troops, expelled the invaders. This further diminished the government's reputation, rendering it almost powerless in time of war. Britain, which played a major role in Persia, was dismayed by the Qajar government's inability to rule efficiently. This inefficiency was the background of a power struggle between Britain and Russia, each nation hoping to control Persia. On 14 January 1921, the British General Ironside chose to promote Reza Khan, who had been leading the Tabriz battalion, to lead the entire brigade. About a month later, under British direction, Reza Khan's 3,000-4,000 strong detachment of the Cossack Brigade reached Tehran.
Question: When approximately did Reza Khan's 3,000-4,000 strong detachment of Cossack Brigade reach Tehran?
Solution:
date