the minimum force is 6 Newtons
Step-by-step explanation
A moment of a force, or a torque, is a measure of a force's tendency to cause a body to rotate. The moment depends on both the force, and on the position at which the force acts, it is given by the expression

where F is the exerted force and d is the distance
Step 1
then, let

now, replace in the formula

therefore, the minimum force is 6 Newtons
I hope this helps you