How does a dragline excavator work​

A dragline usually is refers to as a large bucket excavator that is controlled by a system of pulleys, chains, and ropes that "grabs" the bucket.

i think its

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.