What’s the best answer , a , b , c or d

The Basic Concept

When we look at an object at rest, we say that it is in equilibrium since all the forces being applied on it, cancel out

now, if one of the force was slightly more than the other one in the same case. The object will start to move and NOT be in equilibrium

BUT

if an object is in a vacuum and moving on a frictionless surface, the object will attain equilibrium after some seconds since it will be moving with constant speed and all the forces acting on it will be equal

Hence, if the object is accelerating. we can say with surety that the object is not is equilibrium since from the second law of motion,

F = ma ; when a is a non-zero value, there is definitely some net force being applied on the object

Looking at the given case

in the question, we are given that the object is 'accelerating'  upwards

we proved above that if an object is accelerating, there is some net force on that object and hence the object is NOT in equilibrium

Since the object is accelerating, from the second law of motion:

F = ma; m cannot be zero and if a is a non-zero value as given in the question, there is definitely some net force on the object

Since there is some force being applied on the object, the object is NOT in equilibrium

Conclusion

Since we found that the object is NOT in equilibrium and that there is some net force on the object,

The first option is correct

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia