$3.$In designing springs for electronics, the key consideration is usually:

A$)$ The spring's ability to conduct electricity

B$)$ The color of the spring under electrical stress

C$)$ The spring's aesthetic appeal

D$)$ The resonance frequency with electronic signals

$4.$Helical compression springs are designed to:

A$)$ Conduct electricity efficiently

B$)$ Absorb and store electrical charges

C$)$ Compress under a load and return to their original shape

D$)$ Change color when compressed