The correct answer is A. Parallel.
In parallel connection, each bulb has its own independent path to the power source. This means that if one bulb fails, the others will continue to light. Parallel connection is the most common way to connect light bulbs in street lighting.
In series connection, the bulbs are connected in a single circuit. This means that if one bulb fails, the entire circuit will be broken and all of the bulbs will go out. Series connection is not commonly used in street lighting because it is not as reliable as parallel connection.
In series-parallel connection, some of the bulbs are connected in series and some are connected in parallel. This type of connection is less common than parallel or series connection, but it can be used in some situations where it is desirable to have some redundancy in the circuit.
End-to-end connection is not a valid way to connect light bulbs. This type of connection would create a short circuit and would likely cause the bulbs to burn out.