A 3 yrs old boy is brought to the casualty by his mother with progressive shortness of breath for 1 day.The child has history of bronchial asthma.On examination,the child is blue,gasping and unresponsive.What will you like to do first.

• A. Intubate
• B. Administer 100% oxygen by mask
• C. Ventilate with bag and mask
• D. Administer nebulised salbutamol