Running is great exercise, or it is an inexpensive activity. You can run on a treadmill. You can run outdoors. You should not, therefore, run on icy roads.
B
Running is great exercise. Running is inexpensive, yet you can run on a treadmill. You can run outdoors, however you should not run on icy roads.
C
Running is great exercise, and it is inexpensive. You can run on a treadmill, or you can run outdoors. You should not run on icy roads, however.