CBSE Class 12 · 2024 · MatricesMultiple Choice

For $PQ$ to be defined with $Q$ of order $3\times 2$, the number of columns of $P$ must be $3$; the product then has order (rows of $P$)$\times 2$. A diagonal matrix is square, so the product is $2\times 2$, forcing $P$ to have $2$ rows. Hence $P$ is $2\times 3$.
Correct option: (C) $2\times 3$.