Answer:
Whenever
Step-by-step explanation:
In English language, a conjunction can be defined as an English word that is typically used for connecting two or more clauses, words, phrases or sentences. Some examples of conjunction are but, and, although, because, or, yet, etc.
A subordinate conjunction can be defined as an English word that joins or connects an independent clause and a dependent clause.
A subordinate conjunction does all of the following:
I. It shows how important a main cause is in a sentence.
II. It improves the structure or sound of a literary work.
III. It is used as a transition between an independent clause and a dependent clause.
Some examples of subordinating conjunction are for, since, provided that, though, due to, before, wherever, after, when, once, while, whenever, etc.
In this scenario, the most appropriate subordinating conjunction to use in linking the independent clause and a dependent clause is "whenever." Therefore, the sentence is written as;
"Whenever a car is stuck in the mud, father gets a wrecker to pull it out."