For a particular reaction at $298$ K$,$ Kp $=3\mathrm{.}44510-3.$ When the same reaction is re$-$run at a lower temperature $(155$ K$),$ Kp $=1\mathrm{.}69010-5.$ The reaction is $\_\_\_\_\_\_\_.$a$)$endothermic

exothermic

at equilibrium

complete