Answer:
a. lstColor.SlectIndex = 3
Step-by-step explanation:
Listbox uses index to represent items.
The index starts its count from 0. Meaning that, the first item has an index of 0, the second has an index of 1 and so on.
From the question, the said color is the 4th in the list; going by the simple analysis stated above, it's index is 4-1 = 3.
The syntax for that is
listboxname.Selectedindex = index
i.e.
lstColor.SelectIndex = 3.