What does the word "back" mean

A．More people are dying from skin cancer.
B．A new health campaign is coming up.
C．Sunshine has a lot of benefits.
D．People should spend less time in the sun.

A．Reminding people the benefits of exposure to sunlight.
B．Warning people against the danger of too much sun.
C．Advising people to spend more time in the sun.
D．Improving skin conditions.