Muhammadu Buhari, former Nigerian military ruler and presidential candidate for the Congress for Progressive Change (CPC) speaks during an interview with Reuters at a private residence in Lagos February 19, 2011. Buhari, the main opposition candidate in Nigeria’s presidential election, said he was optimistic it would be a more credible race than in the past but warned events in north Africa showed people would no longer accept a rigged vote. Picture taken February 19, 2011. To match Interview NIGERIA-BUHARI/ REUTERS/Akintunde Akinleye (NIGERIA – Tags: POLITICS HEADSHOT)