Statistics and Probability: JEE Main 2024 Mathematics question

If the variance of the frequency distribution .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-baqh{text-align:center;vertical-align:top} $x$ $c$ $2c$ $3c$ $4c$ $5c$ $6c$ $f$ 2 1 1 1 1 1 is 160, then the value of $c\in N$ is