A 4-year-old child with a 4-day history of wheeze unresponsive to nebulised salbutamol and to adrenaline who is cyanosed and restless (Pa O2 5kPa, Pa CO2 10kPa) should be initially treated with:
a) intravenous bicarbonate
b) intravenous aminophylline
c) immediate intubation and ventilation
d) intravenous diazepam
e) sodium cronoglycate.