Which of the following statements describe Kirchoff's voltage rule?
a. The algebraic sum of the currents in a network of conductors meeting at a point is zero.
b. The algebraic sum of the electromotive forces in any closed loop of a network is equal to the algebraic sum of the products of the currents and the resistances in that loop.
c. The voltage across a resistor is equal to the product of the current through it and its resistance.
d. The total resistance of resistors in series is the sum of their individual resistances.