Twitchy - a kind of junk bond - carries a 10% coupon rate, has a $1,000 face value and matures in 5 years. What is the change in the implicit required return (that is, YTM) of Twitchy, if the current market price of Twitchy, which is $950, falls to $850?

a. -4.10%

b. +2.96%

c. +11.34%

d. -14.30%