N2(g)+3H2(g)<=>2NH3(g) +▲H

if uou are preparing NH3, hiw does the following increase the yield of NH3?
(a) ▲[N2] ▲[H2]
(b) ▲T of the chamber storing NH3
(c) ▲P of the system
(d) ▲[NH3(g)]

* <=> equilibrium
* ▲ change