In India the responsibility maintaining and improving physical standards like, time frequency, mass etc, are given to-

CONCEPT:

• National physical laboratory (NPL): National Physical Laboratory (NPL) is located in New Delhi.
  • It has the responsibility of maintaining and improving physical standards like time-frequency, etc of the country.
  • The national standards of physical measurement at NPL are traceable to international standards.

EXPLANATION:

• Defense Research and Development Organization (DRDO), headquartered in New Delhi, is responsible for the research and development of the  army
• Inter-University Accelerator Center (IUAC) is a nuclear science center located in New Delhi.
• National Physical Laboratory (NPL), New Delhi has the responsibility of maintaining and improving physical standards like time-frequency, etc of the country.
• Bhabha Atomic Research Center (BARC), located in Mumbai, is one of the premier research institutes of our country.

Hence option 3) is correct