A heat engine must give up energy at a lower temperature to do work. This follows from a. the Zeroth Law of thermodynamics
b. the 1st Law of thermodynamics
c. the 3rd Law of thermodynamics
d. the 2nd Law of thermodynamics

a corroding iron, if that's one of your choices

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.