One approach is to solve the system for x and y (which can take a while).
Another approach is that we can create an equation with ONE x and ONE y.

Take:
\(3x+5y=-20\)
\(5x+11y=-39\)

Multiply both sides of the TOP equation by 2 to get:
\(6x+10y=-40\)
\(5x+11y=-39\)

Subtract the bottom equation from the top equation to get: \(x-y=-1\)

GIVEN:
Quantity A: \(x\)
Quantity B: \(y\)

Subtract y from both quantities to get:
Quantity A: \(x-y\)
Quantity B: \(0\)

Since we now know that \(x-y=-1\), we can rewrite Quantity A as follows:
Quantity A: \(-1\)
Quantity B: \(0\)

Answer: B

Cheers,
Brent