Right choice is (d) Blow moulding
To elaborate: In blow moulding process, a heated tube of plastic material is situated between the two halves of mould, then the mould is closed and air or inert gas is usually blown at a pressure of 200 – 400 bars, which helps in expanding of tube outward to occupy the mould cavity. After that the part cools down to get hardened and then the part is ejected from the mould.