A cell in secondary circuit gives null deflection for $2.5\;m$ length of potentiometer having 10 m length of wire. If the length of the potentiometer wire is increased by 1 m without changing the cell in the primary, the position of the null point now is :

Question

$$\begin {array} {1 1} (1)\;3.5\;m & \quad (2)\;3\;m \\ (3)\;2.75\;m & \quad (4)\;2.0\;m \end {array}$$