Answer:
Option (d).
Explanation:
Enzymes are bio-catalyst that can increase the rate of a biochemical reactions occurring in the body of living organisms. The enzymes work at the optimum temperature and pH conditions.
The activity of the enzyme may also be affected by the substrate concentration. The increase in the substrate concentration increases the enzymatic activity at the level and maximum when the enzymes occupy all the site. The enzyme activity will never decrease with the increase of substrate concentration.
Thus, the correct answer is option (d).