Step 1: Understanding the question.
The question asks which activity belongs to the tertiary sector, which involves providing services rather than producing goods.
Step 2: Analysis of options.
(A) Mining: Belongs to the primary sector as it involves extraction of natural resources.
(B) Services: Correct answer. It includes activities like transport, banking, education, and healthcare that provide intangible value.
(C) Food processing: Belongs to the secondary sector, as it involves manufacturing.
(D) Cottage industry: Also belongs to the secondary sector due to production activities.
Step 3: Conclusion.
Thus, the correct answer is (B) Services, as it represents tertiary activities in the economy.