Spark-ignition engines, also known as gasoline engines, are a type of internal combustion engine that use spark plugs to ignite the fuel-air mixture in the combustion chamber. This results in the release of energy that powers the engine. In contrast, diesel engines use compression ignition, steam engines use external combustion, and none of the above options involve spark-ignition engines.

Let's discuss each option in detail:

a) Petrol pumps:
Petrol pumps are not engines, but rather the places where gasoline (petrol) is sold. They are fuel stations where vehicles can fill up their fuel tanks with gasoline. While petrol pumps are crucial for providing fuel for spark-ignition engines, they are not engines themselves.

b) Diesel engines:
Diesel engines are a type of internal combustion engine that use compression ignition rather than spark ignition. In a diesel engine, air is compressed in the combustion chamber to a high pressure and temperature, causing the fuel (diesel) to ignite spontaneously. This is in contrast to spark-ignition engines, where a spark plug ignites the fuel-air mixture.

c) Steam engines:
Steam engines are external combustion engines. They use the energy from steam, which is generated by heating water with an external heat source such as burning coal or wood, to power the engine. The steam expands in a cylinder, pushing a piston and converting heat energy into mechanical work. Steam engines do not involve spark ignition.

d) None of the above:
Since options a) and c) are not spark-ignition engines, and option b) refers to diesel engines that use compression ignition, the correct answer is indeed "None of the above" (d).

In conclusion, spark-ignition engines, also known as gasoline engines, are the engines that use spark plugs to ignite the fuel-air mixture. Petrol pumps, diesel engines, and steam engines do not fall under this category.