Answer:
SERIES-PARALLEL
Step-by-step explanation:
In a series connection, all light bulbs or LEDs are connected to one source and if one of the connecting bulbs burns out, then the remaining bulbs will not light.
In a parallel connection, all bulbs are lighted directly from the power source and as such, if a light bulb is disconnected, other bulbs will still light.
Therefore, it is best for a Christmas light to have a series-parallel connection in the manner of the second picture i.e each segment is first connected in parallel and then in series, this way, if a segment is disconnected, other segments would still light as they do not take power from the disconnected segment.