The correct answer is d) We've chosen two cities to visit: London and Paris
Explanation:
The main purpose of a colon is to introduce a list of elements or a clause that explains a previous sentence. For example, in the sentence "I have three favorite foods: salad, lobster and ice cream" the colon serves to introduce the "three favorite foods". According to this, the colon should be placed after one complete sentence and before a list or an illustration of the sentence.
Thus, the correct option is "We've chosen two cities to visit: London and Paris" because in this case the colon is used to introduce the two cities that were chosen to be visited. Also, the location of this is correct because it is placed after the complete clause "We've chosen two cities to visit" and before a clause that illustrates the first clause.
