Two identical incandescent bulbs are connected in series with an ideal battery and a variable resistor. The slider on the variable resistor is moved so that the resistance of the variable resistor increases. Which statement best describes the change in brightness of the bulbs immediately after the adjustment?
(a) Both bulbs become dimmer because the circuit current decreases.
(b) Both bulbs become brighter because a larger resistance means more power is dissipated in each bulb.
(c) The bulb closer to the battery becomes brighter while the other becomes dimmer.
(d) Both bulbs remain nearly as bright as before because the additional resistance affects only the variable resistor, not the bulbs.