12. The personal protective equipment (PPE) used by medical professionals was in short supply during COVID-19 because ______, and as a result, these professionals often made ______.

a. there were production and supply chain issues; substitutions between mask types and wore face shields

b. of tariffs imposed by the Trump administration; do with only cloth masks

c. of tariffs imposed by the Trump administration; substitutions between mask types and wore face shields

d. there were production and supply chain issues; do with only cloth masks