Explanation:
A. the doctrine of salvation -- Soteriology
It is the theory of deliverance from sin the the consequences.
B. the doctrine of the church -- Ecclesiology
It is the theory of the study of construction and decoration of churches.
C . the doctrine of last things -- Eschatology
It is the theory of death, the final judgement and the destiny of the soul.
D. the doctrine of the Holy Spirit -- Pneumatology
It is the study of Christianity which is concerned with the Holy Spirit
