Ans: B
A may not be true. The proportion of the profit from the sales of pencils of $X$ and $Y$ are the same, not the actual amount the same.
A may not be true. The proportion of the profit from the sales of pencils of $X$ and $Y$ are the same, not the actual amount the same.
B must be true. Note that the larger the angle at centre, the more the profit from the sales of the certain items.
$\begin{array}{rcl}
\theta & = & 360^\circ – 162^\circ-36^\circ -68^\circ – 60^\circ \\
& = & 34^\circ
\end{array}$
Therefore, the sum of the angle at centre of the profit from the sales of pens and notebooks is $94^\circ$. And the sum of the angle at centre of the profit from the sales of rulers and pencils is $104^\circ$. Therefore B must be true.
C is false.
$\begin{array}{rcl}
k\% & = & 100\% – 16\% – 46\% -10\% – 12\% \\
& = & 16\% \\
k & = & 16
\end{array}$
D is false. According to the argument in B, $\theta = 34^\circ$.
