Passage: YJ-91 Ying Ji 91 - Chinese missile based on the Kh-31P. They are also reported to have developed an anti-shipping version with an indigenous active seeker, and are looking to develop this for use in submarines. The name YJ-91 was already in use by 1997, and may have been a Chinese name for the original Russian missiles designated X-31 by the Russians. By 2005, the name YJ-93 was being applied to missiles made in China, but Western reports generally do not distinguish between YJ-91 and YJ-93.An active/passive air-to-air version for use against slow-moving support aircraft, a so-called "AWACS killer", was announced at the 1992 Moscow air show with 200 km (110 nmi; 120 mi) range. That would be less than the 300–400 kilometres (160–220 nmi; 190–250 mi) promised by the Vympel R-37 (AA-13 'Arrow') and Novator R-172 missiles, but a Kh-31 derivative could be carried by a wider range of aircraft. However this may have been mere propaganda; in 2004 the Tactical Missiles Corporation "emphatically denied" that it had ever worked on an air-to-air version of the Kh-31. In 2005 rumours persisted of a Russian AWACS killer based on the Kh-31A anti-shipping model, and of the Chinese adapting the YJ-91, derived from the Kh-31P, for the same purpose.

Question: How do the Chinese hope to use their modified YJ-91?
in submarines