[单选题]
A monochromatic light qe5fc q0x9zoa 7o 7.wsz/9ogds-tpfsb q222obeam oxyzb c1pmxq 6d6(dsri c80 :b7f wavelength λ is diffracted at a single slit of widthdc i zm 0(6bx68d1pycs:7qbrx $b$. After passing the slit, a diffraction pattern is observed on a screen a large distance away. The width of the central maximum is $w$.
The screen is moved closer to the slit. Which of the following changes, done separately, could result in no change in $w$?
A. $b$ is increase;$λ$ is increase
B. $b$ is increase;$λ$ is decrease
C. $b$ is decrease;$λ$ is increase
D. $b$ is decrease;$λ$ is decrease
