Business Continuity is the Risk Management process which assures that, in the event of a disaster condition, an organization will be able to provide at least a minimum level of service while the organization is being restored (recovered) to business as usual in the most effective and cost efficient manner possible.
Business continuity plans prevent a disaster by risk avoidance or mitigation;
the organization is able to maintain at least a minimum level of service
while it is being restored (recovered) to business as usual
Contingency planning is planning what to do when a disaster occurs.
Disaster recovery is restoring the organization after a disaster occurs.
Business Continuity is the most cost-effective option of the three.