Concept:
Directive Principles of State Policy (DPSP) are guidelines given in Part IV of the Indian Constitution to establish social and economic democracy.
Step 1:
The Directive Principles aim to establish a welfare state and promote justice, equality, and good governance.
Step 2:
Promotion of welfare of the people through social, economic, and political justice is a core objective of DPSP.
\[
B \text{ is correct}
\]
Step 3:
DPSP also focuses on improving standard of living and equitable distribution of resources.
\[
C \text{ is correct}
\]
Step 4:
Promotion of international peace and security is mentioned under Article 51.
\[
D \text{ is correct}
\]
Step 5:
The Constitution specifically mentions equal pay for equal work, not equal pay for all jobs.
\[
A \text{ is incorrect}
\]
Step 6:
Hence, the correct combination is:
\[
B,\ C,\ D \text{ Only}
\]
\[
\boxed{\text{(4) B, C, D Only}}
\]