1. The problem states that $P$ and $R$ are coplanar vectors and defines $X = P - R$. 2. To find the vector $X$, recall the vector subtraction rule: $$X = P - R = P + (-R)$$ where $-R$ is the vector $R$ reversed in direction. 3. Geometrically, $X$ is obtained by adding $P$ to the vector $-R$, which points in the opposite direction of $R$. 4. Since $R$ points downward and right, $-R$ points upward and left. 5. Adding $P$ (pointing right) to $-R$ (pointing upward and left) results in a vector $X$ that points upward and left. 6. Among the diagrams, Diagram A shows $R$ downward right, $X$ upward left, and $P$ right, matching the vector addition $X = P + (-R)$. 7. Therefore, Diagram A best represents vector $X$. Final answer: Diagram A.