The properties of being a. clear and bright
b. useful and profitable
make a diamond a gemstone.
c. easy to obtain and beautiful
d. colorful and profitable

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.

c) up

hope this