Explanation:

- The phrase "sun is heated but nice well" is coded as: ctd awr tux fou nyc kpx.

- The phrase "cool girls home are sun" is coded as: ctx tux nxw pqr sit.

- The phrase "laptop home but girls well" is coded as: pqr tar ctd nxw fou.

- The phrase "try pour heated sun cool" is coded as: nyc tux nor pst sit.

- The phrase "well cool love great health" is coded as: sit pox asw fou ktr.

To find the code for "well but cool":

- "well" appears in the phrases coded as: fou, fou, sit.

- "but" appears in the phrases coded as: ctd, ctd.

- "cool" appears in the phrases coded as: sit, sit, fou.

The code for "well but cool" should combine the repeated codes for each word.

- Therefore, the correct combined code is: fou ctd sit.

Answer: Option 4: fou ctd sit