To solve this problem, we need to identify the characteristic feature of transmission tissue.$\newline$Transmission tissue is associated with the style of a flower, which is part of the pistil.$\newline$Let's analyze the options:$\newline \bullet$Option 1: Hollow style - A hollow style does not contain transmission tissue. It is a tube-like structure that allows pollen tubes to grow through it.$\newline \bullet$Option 2: Solid style - A solid style contains transmission tissue. This tissue facilitates the growth of pollen tubes by providing nutrients and guidance.$\newline \bullet$Option 3: Dry stigma - A dry stigma does not have transmission tissue. It is adapted to capture pollen grains without a sticky surface.$\newline \bullet$Option 4: Wet stigma - A wet stigma is sticky and helps in capturing pollen grains, but it does not contain transmission tissue.$\newline$Therefore, the correct answer is Option 2: Solid style, as it is the characteristic feature of transmission tissue.