Apeer group is a group composed of equal age individuals with similar characteristics.
a. primary
c. school
b. mass
d. secondary

D. secondary

Two groups: primary and secondary
The primary groups has stronger and deeper relationships with its member/s than secondary groups, many of which are superficial gatherings and surface dealings.

Primary groups include:
1. Family
2. Lover
3. Husband/Wife 

Secondary groups:
1. Colleagues
2. Classmates
3. Friends
4. Acquaintance

Idont know but good luck; )