Explanation:

Both statements are correct.

• Researchers have discovered the world's deepest blue hole situated in the eastern Yucatán Peninsula also known as Taam Ja' Blue Hole (TJBH), known as Taam Ja' Blue Hole (TJBH). 

• Chetumal lies at the mouth of the Hondo River on the Bay of Chetumal (an extension of the Caribbean Sea), at an elevation of 20 feet (6 metres) above sea level.

• It was founded on the site of a former Mayan settlement. During the colonial era, control of Chetumal was fiercely contested between Spanish conquistadores and indigenous Maya.

Hence option 3rd is correct.