A total resistance of 3.0 Ω is to be produced by combining an unknown resistor R with a 12 Ω resistor. What is the value of R and how is it to be connected to the 12 Ω resistor?
A. 4.0 Ω, parallel
B. 2.4 Ω, parallel
C. 4.0 Ω, series
D. 24 Ω, series