Please choose the correct ending to complete the given sentence: Work World: [header] How to avoid workplace flu [title] Discover when a shot will be available. [step] The flu shot is made available at the same time each year. A group of private pharmaceutical companies produce the vaccine and distribute it to doctor's offices and medical facilities.

Ending1: Usually shipments are made in july or august, and doctors are told to start giving the shot as soon as they receive it. [substeps] The vaccine supply usually runs out in late fall, around october, depending on how many people seek out a flu shot. Ending2: It is required to be administered by the same medical corporation which administered the vaccine. Another medical corporation will administer the dose at the same time each year throughout their country. Ending3: Active marketing campaigns place this offer in place, reminding customers that antivirus patients are alert to various viruses. Medical services organizations provide specialized treatments to treat flu viruses. Ending4: These companies can give you an idea of what your target doses of the flu will be in advance of the upcoming outbreak. [substeps] Call the check-in office at your current location and ask them about the flu shot.

Answer format: ending1/ending2/ending3/ending4