We consider ads for a keyword. The search engine offers 2 links. The first link has a frequency of 300 clicks/day, and the second link a click frequency of 270 clicks/day. There are 2 bidders, A and B. Bidder A values the click at $6 and bidder B values the click at $4. Consider the following assignment: bidder A gets the first position and pays $3/click, while bidder B gets the second position and pays $1.5/click.

Is this assignment stable? If not, identify a blocking pair (and explain why it is a blocking pair). If yes, justify your answers.