Lucknow: Stepping up its offensive against the BJP, Government on Saturday said the opposition party should ask its Chief Ministers to resign in the Coalgate row since the state governments decide who gets the mining lease. 'The basic question is that who executes the lease,' Union HRD Minister Kapil Sibal said, two days after the Centre made public letters written to it by BJP and other non-Congress state chief ministers strongly opposing auction of coal mines.