Step 1: About SEBI. The Securities and Exchange Board of India (SEBI) is the regulator of the securities market in India. Step 2: Chairman. In 2011, U.K. Sinha was appointed as the Chairman of SEBI, succeeding C.B. Bhave. Step 3: Other names. The other options are not linked to SEBI chairmanship. Step 4: Conclude. Hence, the correct answer is U.K. Sinha.
\[
\boxed{\text{U.K. Sinha}}
\]