In a YDSE $\lambda =60 \;nm\; D= 2m\;\lambda=6 mm$. Find the positions of a point lying b/w third maxima and third minima where the intensity in three - fourth of maximum intensity on the screen .

Question

$(a)\;5.67\;mm \\ (b)\;4.67\;mm \\ (c)\;6.67 \\ (d)\;3.67\;mm $