Which option completes the text below correctly?

Marine Corps fitness test offers smart alternative to running

Marines of any age can now conduct the rowing portion of the PFT if they have a medical chit proving they are incapable______completing the running test. (CpI. Jeff Drew/ Marine Corps)

The Marine Corps is making changes______its Physical Fitness Test, allowing Marines to replace the three-mile running portion of the PFT ______ a 5,000- meter stint on a rowing machine.

Marines seeking to do that will require a medical chit to prove and explain why they can’t run. But it will allow fit and hard-working Marines to still earn a top score______ their fitness test without risking unnecessary injury.

It comes at a time when the entire military is wrestling______issues of standards and fitness.

(Adapted from https://www.navytimes.com)