One of the similarities between electric and magnetic fields is that they both
always form closed loops.
A. True
B. False

FALSE

Explanation:

Electric fields are produced by two kinds of charges, positive and negative. Magnetic fields are associated with two magnetic poles, north and south, although they are also produced by moving charges. Like poles repel and unlike poles attract.

Electric lines of force due to two positive charges start from either charge and end at infinity. In all cases we see that electric lines of force , either from infinity or from a positive charge never come back to the same point, because the field lines starts (or diverges) from the positive charge and terminate (or converges) on negative charge. If the electric field lines form closed loop, these line must originate and terminate on the same charge which is not possible because  electric field lines always moves from positive to negative and hence they don't form closed loops.