The last stage of trials of ______ COVID-19 vaccine have been paused after a participant fell ill ?

a) Moderna
b) AstraZeneca 
c) Sputnik V
d) None of these

The last phase of clinical trials of the COVID-19 vaccine developed by Oxford University and AstraZeneca has been put on hold after one of the participants fell ill in the United Kingdom. AstraZeneca described the pause as a “routine” pause in the case of “an unexplained illness”.