Does h3po4+3koh=k3po4+3h2o represent an acid base reaction

Yes it does represent an acid base reaction because H stands for acid and OH stands for base. Clearly we can see those symbols in the reactants. Also, products of acid base reaction are usually salts and water.

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Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.

No because it not possibly