I recently went to the dentist for a procedure that required me to have laughing gas

I recently went to the dentist for a procedure that required me to have laughing gas (nitrous oxide or N2O). I specified that I wanted EXACTLY 2.500 x 1024molecules of this gas delivered to me. If he was going to be my dentist he had to prove to me he knew a little chemistry. How many grams would he have to deliver? A.1.100 × 103 B.44.01 C.182.7 D.16.61