The question is basically setting up a situation similar to that of a competitive inhibitor. They say that higher concentrations of pyridoxal phosphate increases the activity of the enzyme to normal levels. Similarly, when you have a competitive inhibitor and increase the concentration of substrate, the enzyme can achieve the same Vmax as if without the inhibitor.
I’m not sure about this one but the way I thought about it was that since the confidence interval included 1, it was not significant. And thus p value must be above 0.05