Two Individuals, a and B, Consume Two Goods $x$ And $y$ Together They Have 4 Units Of Goods

Two individuals, A and B, consume two goods, $x$ and $y$ . Together they have 4 units of $x$ and 8 units of $y$ . For Consumer A the $M R S _ { x , y } ^ { A } = { } ^ { 5 x } / 3 y$ and for Consumer B the $M M R S _ { x , y } ^ { B } = 3 x / y$ . Which of the following allocations is an efficient allocation of goods $y$ and $y$ ?

A) Consumer A has 5 units of $x$ and 3 units of
$y$ , and Consumer B has 3 units of $x$ and 1 unit of $y$ .
B) Consumer A has 3 units of $x$ and 5 units of
$y$ , and Consumer B has 1 unit of $x$ and 3 units of $y$ .
C) Consumer A has 2 units of $x$ and 6 units of
$y$ , and Consumer B has 6 units of $x$ and 2 units of $y$ .
D) Consumer A has 7 units of $x$ and 2 units of $y$ , and Consumer B has 1 unit of $x$ and 6 units of $y$ .