I know that the answer to the question "Who sends the Korean Presbyterian missionaries out all over the world?" is in "Korean Presbyterian denominations are active in evangelism and many of its missionaries are being sent overseas, being the second biggest missionary sender in the world after the United States. GSM, the missionary body of the "Hapdong" General Assembly of Presbyterian Churches of Korea, is the single largest Presbyterian missionary organization in Korea. In addition there are many Korean-American Presbyterians in the United States, either with their own church sites or sharing space in pre-existing churches as is the case in Australia, New Zealand and even Muslim countries such as Saudi Arabia with Korean immigration.". Can you tell me what it is?
A:
GSM