Correct Answer - Option 2 : 7.5 cm

**Explanation**

Given,

Length = 60 m

Gradient = 1 in 20

Gradient = h/L

\(\tan {\rm{\theta }} = \frac{1}{{20}} = \frac{h}{{60}}\)

⇒ h = 3 m

We know slope correction is given by

\({\rm{Slope\;correction}} = \frac{{{{\rm{h}}^2}}}{{2{\rm{L}}}}\)

\({{\rm{C}}_{\rm{S}}} = \frac{{{{\left( {3} \right)}^2}}}{{2 \times 60}} = 0.075{\rm{\;m}}\)

CS = 0.075 m = **7.5 cm** (Negative)

**Note: **

**Correction due to slope will always be negative because slope distance is greater than corresponding horizontal distance.**