Utilize the input text as a context reference, choose the right relationship between 'MedImmune' and 'AstraZeneca' from the options.
Options: manufacturer, platform, original broadcaster, parent organization

Companies like Pfizer, Sanofi, Merck, AstraZeneca and MedImmune continue to disinfect with a safe SteraMist BIT chemical protecting their operator, facility and the environment, while providing the confidence to the American population that we will produce sterile vaccines.
parent organization