Given the task definition and input, reply with output. In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: a ladder 14 feet long is leaning against a wall that is perpendicular to level ground . the bottom of the ladder is 9 feet from the base of the wall . if the top of the ladder slips down 1 feet , how many feet will the bottom of the ladder slip ? 
Options: a ) 4 , b ) 10 , c ) 18 , d ) 19 , e ) 25

b