Changed tracks
An obvious change was made to the Tiger's track design in mid 1943. A new type of track link with better grip was introduced.
This photo shows the new type of track. They have diagonal ridges on the outer face.
This change was made during production of what we call "Mid" Tigers. More than half of "Mid" production Tigers were equipped with the new tracks [1, see 3.4.1.12] .
Tracks in this kit
This kit includes two full sets of tracks. One is the original kind and the other is the later ridged kind. The instructions tell you to choose either one at your discretion, but they don't associate track types with the kit's decal options.
In fact, to be accurate, you should use only the ridged type of track (the "B" sprue). This kit builds a Tiger from the end of the "Mid Tiger" period, November-December 1943, and the ridged tracks were the only ones manufactured at that time. I believe that the "A" sprue was included in this kit by mistake.