Final answer:
The use of a semicolon is appropriate to connect two independent clauses that are closely related, especially when they are not joined by a coordinating conjunction. Option a.
Step-by-step explanation:
The correct use of a semicolon is to connect two independent clauses that are closely related in meaning and are not joined by a coordinating conjunction.
A semicolon can be used when the second clause restates or further explains the first clause. If there is no coordinating conjunction, and the sentences are closely related, a semicolon can join them effectively.
For example, 'Road construction in Seattle has hindered travel around town; streets have become covered with bulldozers, trucks, and cones.'
Here two related independent clauses are joined with a semicolon. Another example is, 'It rained heavily during the afternoon; however, we still managed to have a picnic.' The second independent clause is linked to the first with a semicolon followed by a conjunctive adverb (however) and a comma.
To summarize the options given:
A semicolon should be used between two independent clauses without a conjunction.
A semicolon is not necessary before a coordinating conjunction because the conjunction itself joins the clauses.
While not mentioned in relation to semicolons specifically, a colon is more appropriate before a list or an explanation that directly follows an independent clause.
It's also important to note that semicolons are used in a series to separate items that contain commas to avoid confusion. So Option a.