Step 1: Understanding the Biological Weapons Treaty
- The treaty is formally known as the Biological Weapons Convention (BWC).
- It was the first multilateral disarmament treaty banning the development, production, and stockpiling of biological and toxin weapons.
Step 2: Year of signing
- The BWC was signed in 1972 and came into force in 1975.
- It remains a cornerstone in international efforts to prevent the use of biological warfare.
Step 3: Analyzing options
- 1970: Incorrect, no such treaty signed in this year.
- 1972: Correct year of signing.
- 1990: Incorrect, far too late.
- 1992: Incorrect, but relates to later disarmament discussions.
Step 4: Conclusion
Thus, the Biological Weapons Treaty was signed in the year 1972.
\[
\boxed{\text{Correct Answer: (B) 1972}}
\]