Given the following passage  "Baptists subscribe to a doctrine that baptism should be performed only for professing believers (believer's baptism, as opposed to infant baptism), and that it must be done by complete immersion (as opposed to affusion or sprinkling). Other tenets of Baptist churches include soul competency (liberty), salvation through faith alone, Scripture alone as the rule of faith and practice, and the autonomy of the local congregation. Baptists recognize two ministerial offices, pastors and deacons. Baptist churches are widely considered to be Protestant churches, though some Baptists disavow this identity.",  answer the following question. Note that the answer is present within the text.  Question: Which of the following is not a type of baptism: affusion, liberty or sprinkling?
A:
liberty