In a single slit diffraction experiment, a slit of width 'd' is illuminated by red light of wavelength 650 nm . For what value of ' \( d \) ' will the first maximum fall at an angle of diffraction of \( 30^{\circ} \) ?

A 1.39 nm

B \( 1.75 \mu \mathrm{~m} \)

C \( 1.95 \mu \mathrm{~m} \)