Which of the following statements is FALSE regarding evaluating networks of resistors and batteries?

a. The sum of the current around any closed loop must equal to zero
b. When following the direction of a (proposed) current, the voltage change across a battery is positive ( a voltage gain)
c. The sum of the currents entering a junction (node) must equal the sum of the currents exiting that junction (node).
d. When running against the direction of a (proposed) current, the voltage change across a resistor is positive ( a voltage gain)
e. When following the direction of a (proposed) current, the voltage change across a resistor is negative ( a voltage drop)
f. The sum of the voltages differences around any closed loop must equal zero.