Task: Question Answering
Input (English): Problem: when the oil from a circular cylinder leaked , the formula for the speed of the leak is v = kh ^ 2 , where h was the height of the remaining oil and k was constant . if the height of the cylinder is 4 , the speed of the leak is v â € ™ , when the height of the oil remaining is 12 , what was the speed of the leak , in terms of v â € ™ ? 
Options: ['a ) 9 v â € ™', 'b ) 4 v â € ™', 'c ) v â € ™ / 2', 'd ) v â € ™ / 4', 'e ) v â € ™']
Output (English): a