context: During her fourth war patrol (13 January 1943 - 26 February 1943), Gato torpedoed and sank transport Kenkon Maru 21 January; cargo ship Nichiun Maru on 29 January; and cargo ship Suruya Maru on 15 February—all off New Georgia, Solomon Islands. On her fifth war patrol (19 March - 6 June 1943), she landed an Australian Intelligence party at Toep, Bougainville Island, 29 March 1943, and evacuated 27 children, nine mothers, and three nuns, transferring them 31 March to the submarine chaser SC-531 off Ramos Island, Florida Island. During a submerged radar attack approach 4 April 1943, between Tanga Islands and Lihir Islands, she was shaken so violently by three exploding depth charges that she returned to Brisbane for temporary repairs 11 to 20 April. Gato landed more Australian commandos at Toep Harbor 29 May, transported more evacuees to Ramos Island, and then reconnoitered off Tarawa Atoll in the Gilbert Islands before putting in at Pearl Harbor 6 June 1943.
question: Which ships did Gato sink on her fourth war patrol?
answer: Kenkon Maru