Weknow that width $\left(\mathrm{B}_0\right)$ of central maxima $\beta_0=\frac{\mathrm{D} \lambda}{\mathrm{d}}$ where $\mathrm{D}$ is the distance between slit and screen $\lambda$ is the wave length of source does not change.
(a) When increases the width of the hole 'd' increase so, size decrease.
(b) When, size of hole is decrease, then the light energy is distributed over a small area and intensity $\propto \frac{1}{\text { area }}$ as area is decreasing so intensity increases.