Answer:
The correct answer is When.
It demonstrates a Relationship of Time.
Step-by-step explanation:
Subordinating conjunctions are words or phrases that connect a dependent clause to an independent clause. The dependent clause adds information about the idea expressed by the independent clause.
There are two main groups of relationships shown by subordinating conjunctions:
Because, since, so, as long as, even if.
Once, after, before, whenever.
In the given sentence, the subordinating conjunction "when" determines that the action "come to the picnic" will only be performed after the person finishes the main action "get home from soccer."