Consider the following statements:
- Coal ash contains arsenic, lead and mercury.
- High content of silica is found in coal-fired power station's emissions.
- Coal-fired power plants release sulphur dioxide and oxides of nitrogen into the environment.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 3 only
(d) 1, 2 and 3