DSE 2018 Question 3: General equilibrium and exchange economies

Consider an exchange economy with two agents, 1 and 2, and two goods, $X$ and $Y$. Each agent's consumption set is $\mathbb{R}^2_+$. The endowments of agents 1 and 2 are $(10, 1)$ and $(0, 9)$ respectively (the first entry is a quantity of $X$, the second a quantity of $Y$). If $a > c$, or $a = c$ and $b > d$, then Agent 1 strictly prefers bundle $(a,b)$ to $(c,d)$. If $b > d$, or $b = d$ and $a > c$, then Agent 2 strictly prefers bundle $(a,b)$ to $(c,d)$. Which of the following allocations is a competitive equilibrium allocation?