Which is a true statement about tobacco and smoking?

a.
tobacco ads can be within 1000 feet of schools and playgrounds.

b.
no more than 5 million americans use smokeless tobacco.

c.
every day almost 5,000 american young people smoke their first cigarette.

d.
of all teens who smoke a first cigarette, only 10% will become regular smokers.

Investigator a has biological specimens that are coded and linked to identifiers of the source individuals. investigator a provides the specimens to investigator b but does not provide the individual identifiers. investigator b agrees not to re-identify the source individuals. is investigator b's research using the biospecimens human subjects research according to the definition of human subjects research in the federal regulations?