Scatter with smooth line - X axis values

[calabresino]

Hello,

I am working on a scatter smooth line chart and I am having an issue with the X axis.

I have 5 points on my charts and excel is doing an interpolation to get the smooth line.

Values one the X axis go from 0 to 6 while I would like to customize it to have:
"Put 40" for point 1, "Put 25" for point 2, "ATM" for point 3, "Call 25" for point 4, etc

How could I customize the values?

thanks in advance