Final answer:
The resistance between two diagonal points of the square wire would be 6Ω. Therefore, the correct option is C.
Step-by-step explanation:
To find the resistance between two diagonal points of a square wire, we need to consider the equivalent resistance of the wire. Since the wire is bent in the form of a square, it can be divided into two equal halves along the diagonals. Each half will have a resistance of 6Ω, as it is half the resistance of the complete wire. Therefore, the resistance between two diagonal points of the square wire would be 6Ω (Option C).