A diesel engine has

Answer: Option C

There are different valves used in a diesel engines. Now it depends on which valve numbers you want to know.
Inlet valves - inlet valves generally allow the intake air to enter into the combustion chamber. These may generally vary from 1 to 2 per cylinder in numbers depending on air quantity and open timings.
Exhaust valves - likewise they allow the exhaust gas to allow burnt out gas from chamber to exhaust manifold. They are also 1 to 2 per cylinder in numbers.