Final answer:
The correctly punctuated phrase is "In the hallway, Mrs. Leong hung a new painting."
Step-by-step explanation:
The phrase that is correctly punctuated is option C: In the hallway, Mrs. Leong hung a new painting. This sentence follows the correct punctuation rules for using commas. Commas are used to set off non-essential information, such as the phrase "In the hallway" in this case. So, the correct placement of the commas makes this option the right choice.
Learn more about Punctuation in English sentences