The Following Matrix Shows the Payoffs for an Advertising Game

The following matrix shows the payoffs for an advertising game between Coke and Pepsi.The firms can choose to advertise or to not advertise.Numbers in the matrix represent profits; the first number in each cell is the payoff to Coke.(Numbers in millions.)
$\begin{array}{c}\begin{array}{|l|}\hline \text { Coke (rows) / Pepsi}\\ \text { (columns)}\\\hline \text { Advertise}\\\hline \text { Don't Advertise}\\\hline \end{array}\begin{array}{l|}\hline\\ \text { Advertise}\\\hline(10,10)\\\hline(-50,500)\\\hline\end{array}\begin{array}{l|}\hline \\\text {Don't Advertise}\\\hline (500,-50)\\\hline (100,100)\\\hline \end{array}\end{array}$
a.Explain why this would be described as a Prisoner's Dilemma game.
b.Explain the probable outcome of this game.