what rate does the "interest rate" refer to? is it YTM? or coupon rate?

Interest Rate Risk . Price Risk. - Change in price due to changes in interest rates. - Long-term bonds have more price risk than short-term bonds. - Low coupon rate bonds have more price risk than high coupon rate bonds. Figure 6.2 Figure 6.2: Interest rate risk and time to maturity This graph has the intereat rate (percent) on the x-axis and the bond value (in dollars) on the y-axos. The x. axls goes fromzero to twenly counting by fives. The y-axis goes from zero to $2.000 counting by $500. The graph displays two inferseding curves. The curvin for the 1-your bond is so stight that it alinost looks the a line whit a slght negatwo slope