Answer:
Semicolon.
Explanation:
Punctuation is the correct use of the different punctuation marks in such a way that they help improve and make the sentence correct. This involves the use of such signs to make sentences better and also to properly structure the sentences.
In the given sentence, the speaker lists multiple cities that he'd/ she'd visited. The list includes (i)Shanghai, China, (ii) Angeles, California, and (iii) London, England. And to correctly punctuate the list of cities, we must use a semicolon in between the names of these cities. And since a comma is already used, a semicolon will be used to separate between the cities. Therefore, there will be a semicolon after California.
Thus, the correctly punctuated sentence will be-
<em>While searching for employment, I traveled to Shanghai, China; Los Angeles, California; and London, England.</em>