Correct Answer - Option 4 : Remains unchanged
Concept of Sag (s):
The distance between the highest point of electric poles or towers and the lowest point of a conductor connected between two poles or towers.
Span length: It is the shortest distance between two towers or poles.
\(S = \frac{{W{l^2}}}{{8T}}\)
Where,
S is the sag of the conductor
W is the weight of the conductor
l is the span length of the conductor
T is the working tension on the conductor
Here in the question
height of the supporting towers is increased by 25 % which is independent of sag. Hence there will be no change in sag.