After losing his right arm to an injury sustained in World War I, the Austrian pianist Paul Wittgenstein decided to focus on pieces written for the left hand instead of to quit his professional piano-playing career.

a) decided to focus on pieces written for the left hand instead of to quit
b) decided to focus on pieces written for the left hand instead of quitting
c) decided he ought to focus on pieces written for the left hand as opposed to quitting
d) decided to focus on pieces written for the left hand rather than quitting
e) decided to focus on pieces written for the left hand rather than quit