I would say b. c. & d. because the question is asking how to stay safe before, not during.
Go for longer reps each day then rest and it will improve your lower body strength.
Oh there have been plenty.
STI's for example including HIV (human Immunodeficiency virus) has definitely boosted the awareness of caution and avoiding risky behaviors in both sexual terms and reducing exposure to bodily fluid via blood in work, or IVDA (intravenous drug abuse) needle sharing.
Additionally potentially dangerous and very infectious diseases like the Flu have put an emphasis on the very basic disease prevention of washing ones hands, covering your sneezes, wearing face masks during exposure, and getting vaccinated as well.
And these are merely two examples of how hundreds of disease shaped out infection control protocols and norms.
