Consider the actual and forecast values contained in the table.

$\backslash$table$[[$#$,$Actual,Forecast,#$,$Actual,Forecast$],[1,10,10\mathrm{.}8,6,26,24\mathrm{.}5],[2,13,13\mathrm{.}6,7,28,27\mathrm{.}2],[3,17,16\mathrm{.}3,8,29,29\mathrm{.}9],[4,19,19,9,32,32\mathrm{.}6],[5,22,21\mathrm{.}7,10,35,35\mathrm{.}3]]$

At which observation is the tracking signal at its maximum value?

Observation #$4$

Observation #$5$

Observation #$7$

Observation #$6$