The correct choice is Buffers.
Buffers contains both acids and bases in equilibrium.when base is added to buffers, they adjust the pH value by releasing hydrogen ions.when acid is added to buffers, they adjust the pH value by consuming hydrogen ions. hence these substances resist any change in their pH value by releasing or absorbing hydrogen ions.This process keeps the pH value constant.
Answer:

Explanation:
In the question given :
Pressure is constant
Therefore, Work done, 
Pressure, P=1.01 × 105 Pa.
Final volume, 
Initial volume, 
Therefore, W=8.58\times 10^{5}\ J.
Also, Heat Given, 
Also, according to First law of thermodynamics:

Hence, this is the required solution.
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