Concept:Lagos was formally annexed by the British as a colony in 1861.Explanation:The annexation took place on 6 August 1861.It was carried out under the threat of force by Commander Beddingfield of HMS Prometheus.He was accompanied by the Acting British Consul, William McCoskry.This event marked the beginning of the Lagos Colony under British rule.The direct annexation in 1861 is different from the earlier bombardment of Lagos in 1851.Therefore, the correct year is 1861.Answer:A. 1861