Given the Following Parents and Components, How Many Bs Are

Multiple Choice

Given the following parents and components, how many Bs are required to make an X? Quantities are shown in brackets.
$$\begin{array} { l l l } \text { Parent } & \mathrm { X } & \mathrm { A } \\\text { Component } & \mathrm { A } ( 2 ) & \mathrm { B } ( 2 ) \\& \mathrm { B } ( 1 ) & \mathrm { D } ( 1 ) \end{array}$$

A) 1
B) 2
C) 3
D) 4
E) 5