PAN is called as

$\begin{array}{1 1}(a)\;\text{Peroxy acetyl nitrate}\\(b)\;\text{Peroxy nitrate}\\(c)\;\text{Peroxy acetic nitrate}\\(d)\;\text{Peroxy acetyle nitric}\end{array}$

PAN is called as Peroxy acetyl nitrate
Hence (a) is the correct answer.