The main reason commonly cited for military intervention in Nigerian politics is the perceived incapability of civilians to govern. Military officers who staged coups in Nigeria consistently justified their actions by pointing to corruption, mismanagement, ethnic tensions, political instability, and economic decline under civilian administrations.
From the first military coup in January 1966 through subsequent takeovers, the military presented itself as a corrective force stepping in because civilian politicians had supposedly failed in their duty to govern effectively. Allegations of widespread corruption, rigging of elections, abuse of power, and inability to maintain law and order were the standard justifications offered by coup plotters.
The other options are not valid reasons for military intervention. International pressure for human rights would more likely discourage military takeovers, not encourage them. The desire for civil government is the opposite of military intervention - it is what leads to transitions back to civilian rule. "Civilians' dislike for power" is factually inaccurate - civilian politicians have historically competed vigorously for political power in Nigeria.
It is important to note that while the military cited civilian failure as justification, military regimes themselves were often characterised by the same problems of corruption and mismanagement they claimed to be correcting.