Experimental observation in a single slit experiment show that the intensity has a central maximum at θ = 0 and other secondary maxima at θ = ______________. (where 'θ' is the angle between the central line and the line joining the midpoint of the slit of width 'a' to any point 'P' on the screen, 'λ' is the wavelength of the light and where n = ±1, ±2, ±3, ....)

• A. (n + 1 / 2) λ / a
• B. nλ / a
• C. (n + 1 / 2) a / λ
• D. na / λ