Filter the three base grids by "Karn has exactly two yes-votes," then read the answer straight off whichever grid is left, without re-deriving the puzzle from the original rules again.
Draw a 3-by-3 grid, one row per member (Arjun, Karn, Bhim) and one column per bill (recreation, school, tax), and fill in only what the passage states directly: Arjun is yes on recreation and no on school; Karn is no on recreation; Bhim is no on tax.
Recreation needs exactly two yes-votes overall. Arjun already supplies one of those two. Karn is a confirmed no, so the second yes on recreation cannot be Karn, which leaves only Bhim. Fill in Bhim as yes on recreation right away, before touching anything else.
School needs exactly one yes-vote overall, and Arjun's cell there is already a no, so the single yes on school belongs to either Karn or Bhim, not both. Tax needs exactly one yes-vote overall, and Bhim's cell there is already a no, so the single yes on tax belongs to either Arjun or Karn, not both.
Every row of the grid needs at least one yes and at least one no. Arjun's row already has a yes (recreation) and a no (school), so Arjun's tax cell can go either way without breaking this rule. Bhim's row already has a yes (recreation) and a no (tax), so Bhim's school cell can go either way too. Karn's row so far has only a no (recreation), so Karn's row needs at least one yes somewhere among school and tax, or the row rule breaks.
Every row in all three grids carries at least one yes and one no, and every column total matches the passage's counts, so all three grids are valid, and since the school/tax assignment choices above cover every possibility, no fourth grid exists.
Row totals for Karn in each grid: Grid A gives Karn 1 yes (school only). Grid B gives Karn 2 yes (school and tax). Grid C gives Karn 1 yes (tax only). Only Grid B has Karn at exactly two yes-votes, so Grid A and Grid C are both filtered out by this question's condition, leaving Grid B as the single surviving world.
Grid B in full: Arjun is yes only on recreation, Karn is yes on school and tax, Bhim is yes only on recreation.
Since Grid B is the only grid consistent with "Karn has exactly two yes-votes," whatever holds in Grid B must hold whenever this question's condition is true. "Karn votes for the school bill" is the one statement confirmed by Grid B, so it is the statement that must be true.