The correct answer is (c) and (d). Ocean trenches are long, narrow depressions on the seafloor. These trenches are the deepest parts of the ocean - and some of the deepest natural spots on Earth. Ocean trenches are found in every ocean basin on the planet, although the deepest ocean trenches are found in the Pacific as part of the so-called “Ring of Fire” that also includes active volcanoes and earthquake zones. ​Important Points Tonga trench is located in the south-west Pacific Ocean and at the Kermadec Tonga Subduction Zone’s northern end, the Tonga Trench lies around 10.882 km below sea level. Mariana trench is located in the western Pacific Ocean, the Marina Trench is considered to be the deepest part of the Earth’s surface. In fact, it is the Challenger Deep in the Mariana Trench that is known as the deepest point. Kurile - Kamchatka Trench is another deepest part of the ocean belonging to the Pacific Ocean, this trench lies at a considerable depth of 10.5 km below sea level. Java Trench, also called Sunda Double Trench, deep submarine depression in the eastern Indian ocean that extends some 2,000 miles (3,200 km) in a northwest-southeast arc along the southwestern and southern Indonesian archipelago. The South Sandwich Trench is a deep arcuate trench in the South Atlantic Ocean lying 100 kilometres (62 mi) to the east of the South Sandwich Islands. It is the deepest trench of the Southern Atlantic Ocean, and the second deepest of the Atlantic Ocean after the Puerto Rico Trench. [ alt="6023a3e4c31ecdbe040e8800 16376674194341" src="//storage.googleapis.com/tb-img/production/21/11/6023a3e4c31ecdbe040e8800_16376674194341.png" style="width: 450px; height: 258px;">