A transistor oscillator is
(i) An amplifier with positive feedback
(ii) An amplifier with reduced gain
(iii) The one in which DC supply energy is converted into AC output energy. Then

• A

  All (i), (ii) and (iii) are correct
• B

  (i) and (ii) are correct
• Correct answer
  C

  (i) and (iii) are correct
• D

  (ii) and (iii) are correct

Hence, the correct answer is option: 'C'.