Answer:
c) triple(3x)
Step-by-step explanation:
The equation for kinetic energy is:

if the mass triples we will have that the new kinetic energy 
 is:
 is:

which can also be written as:

and 
 is the original kinetic energy
 is the original kinetic energy 
 , so:
, so:

⇒the new kinetic energy is three times the original kinetic energy.
the answer is: his kinetic energy will triple (3x) which is option c.