In an experiment to measure the wavelength of light using a double slit, it is found that the fringes are too close together to easily count them. To spread out the fringe pattern, one could

halve the slit separation

Explanation:

As we know that

In YDS experiment, the equation of fringe width is as follows

where,

D denotes the separation in the middle of screen and slits

d denotes the distance in the middle of two slits

And to increase the Δx we have to decrease the d i.e, the distance between the two slits

Hence, the first option is correct

because if the tool that you are using is not balanced it there would be false mass.