Indifference curves and budget lines — practice question

In the diagram, PQ shows the consumer’s initial budget line. The consumer’s income rises from $80 to $120 and, at the same time, the prices of X and Y alter. If the consumer’s budget line is now RS, what are the updated prices of X and Y?

• Aprice of X $4; price of Y $12
• Bprice of X $6; price of Y $10
• Cprice of X $10; price of Y $8
• Dprice of X $12; price of Y $6