Which of the following shot pellets has the smallest diameter?

The choice indicating No. 9 shot pellets is the correct answer because they are the smallest in diameter among the options provided. In shotgun terminology, the numbering system for shot size works inversely; the higher the number, the smaller the individual pellets. No. 4 and No. 7 1/2 pellets are larger than No. 9, which reflects the general pattern in shot size nomenclature. 00 Buck is also significantly larger than No. 9, as it consists of larger pellets designed for different types of hunting and shooting applications, typically offering more impact. Consequently, No. 9 shot is preferred for small game and bird hunting due to its smaller size, which allows for a denser spread and reduces the likelihood of damaging the meat of smaller targets.