P, Q, R and S are four wires of resistances 3, 3, 3 and 4 Ω respectively. They are connected to form the four arms of a wheatstone bridge circuit. The resistance with which S must be shunted in order that the bridge may be balanced is _______.
Fill in the blank with the correct answer from the options given below
1
14 Ω
2
12 Ω
3
15 Ω
4
7 Ω