Grammatically, it is best to avoid use of verbs ending in "-ing" where they are not necessary. The correct answer avoids this by using the phrase "owner who started." It is also the most efficient (and least wordy) option. 

The original sentence contains a subordinate clause, "Although I was raised in an English-speaking household," and an independent clause, "I always found French and Spanish much more beautiful." Therefore the comma separating them is correct, and the sentence contains no error. The word "although," especially when used at the beginning of a sentence, is an easy marker for subordinate clauses.

In this question, the original sentence was actually formed by two independent clauses combined with a comma (a comma splice). In order to unite two independent clauses, either one clause must be subordinated, or stronger punctuation must be used. Only the correct answer choice connects the independent clauses with the correct punctuation, in this case, a semicolon.

The list that forms the subject of the sentence, "Angles, Jutes, and Saxons," appropriately separates its items with commas. The comma between "Saxons" and "were" splits the subject of the sentence from the verb, and should be removed. This makes "Angles, Jutes, and Saxons were" the correct answer choice.

The list of names that forms the subject of the sentence is written incorrectly. All lists need to have commas separating their parts from each other for purposes of clarity. The correct answer choice is "Jane, Sally, and Suzy all went to the zoo together."

The list of names that make up the subjects of the sentence all need to be appropriately punctuated. Any such list needs have all the elements set apart from each other; therefore, "Tom, Dick, and Harry have all seen" is the correct answer.

The list that functions as the subject of the sentence needs to have commas separating its elements, distinguishing the different parts. The only answer choice that does this is "Politicians, organizers, and reformers all came together," making it the correct answer choice.

A list like the one in the underlined portion of the sentence must always be appropriately separated out, especially when the elements of the list are two words, like "foreign policy." The only answer choice that clearly delineates the three component parts of the list is "economics, foreign policy, and health care."

Any list like the one used as the subject of the sentence needs to have its elements separated by commas to distinguish the separate parts. The only answer choice that appropriately does this is "The athletes, musicians, and actors," with every other answer choice being grammatically incorrect.

A list like the one in the underlined portion of the sentence always needs to be separated by commas to clearly distinguish between the different elements in the list. The only answer choice that correctly does this is "Rowing, lacrosse, and tennis are," making it the correct answer choice.