If the hydraulic cylinder H draws in rod BC with a constant force of 70N and the 12kg block A has a coefficient of kinetic friction of 0. 25 with the surface, determine the acceleration at C.
a) 4. 83 m/s²
b) 5. 25 m/s²
c) 6. 20 m/s²
d) 7. 15 m/s²