Choose the correct option A; B; C or D to fill in the gaps to make the passage meaningful

V. Choose the correct option A, B, C or D to fill in the gaps to make the passage meaningful.
People are living longer, so there are more (1)…. people. Many young people are doing community service. They help elderly people. They do their shopping. They do their housework. They clean their yards. They (2)…. paint their houses. Some young people work (3)…. hospital volunteers. In America, they are called “candy stripers” (4)…. of the striped pink and white uniform they wear. Others are concerned about the environment and work on neighborhood clean-up campaigns.
1. A. elderly     B. long-lived    C. older     D. A&B are correct
2. A. mainly    B. even    C. mostly    D. partially
3. A. for    B. at    C. as    D. in
4. A. because     B. when    C. though    D. because of