Sentence:  In general , friendly contact with a member followed by contact with a clergyman will account for a major share of recruitment by the churches , making it quite evident that the extension of economic integration through <WSD>co-optation</WSD> is the principal form of mission in the contemporary church ; economic integration and co-optation are the two methods by which Protestants associate with and recruit from the neighborhood . 
Meaning of the word marked with <WSD> tags:  the selection of a new member (usually by a vote of the existing membership)