Calculate the total pressure in a mixture of 4g $O_2\;and \;2g\;H_2$ confined in a bulb of 1 litre at $0^{\large\circ}C$

Question

$(a)\;23.62atm\qquad(b)\;24.32atm\qquad(c)\;26atm\qquad(d)\;25.215atm$