The correct answer is (A) A unit of nautical measure equal to 6 feet or 1.8288 meters. It is used in reporting the depth of water. A fathom is also a unit of volume equal to six cubic feet of ore.

Examples of use:

• A fathom is approximately equal to the distance from fingertip to fingertip of a man's outstretched arms.
  
  
• The pen name, Mark Twain, was the term used on the Mississippi to denote a depth of two fathoms.