Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Beginning in 1979, Nigerians participated in a brief return to democracy when Olusegun Obasanjo transferred power to the civilian regime of Shehu Shagari. The Shagari government became viewed as corrupt and incompetent by virtually all sectors of Nigerian society. The military coup of Muhammadu Buhari shortly after the regime's fraudulent re-election in 1984 was generally viewed as a positive development. Buhari promised major reforms, but his government fared little better than its predecessor. His regime was overthrown by another military coup in 1985.
Which Nigerian leader transferred power in 1979?