Three very long, straight, parallel wires $A$, $B$ and $C$ pass through the corners of an equilateral triangle of side $5.0\ \text{cm}$, at right angles to its plane, as in the figure. Each carries a current of $10\ \text{A}$. In $A$ and $B$ the current flows out of the page, and in $C$ it flows into the page. The wires are held in place, and nothing else is nearby. The point $M$ is the middle of $AB$, and $O$ is the centre of the triangle. Take $\mu_0 = 4\pi \times 10^{-7}\ \text{T m/A}$. Which of the following statements are correct?

Fig. 1: End view of three long parallel wires at the corners of an equilateral triangle of side 5.0 cm. Wires A at the bottom left and B at the bottom right carry 10 A out of the page; wire C at the top carries 10 A into the page. M marks the middle of AB and O the centre of the triangle.