Answer:
Diane couldn't concentrate on General Hospital because Santana, her beagle who had been cooped up in the house all day, wanted to take a long walk around the lake.
Explanation:
Commas in this case go after the word Santana and after the word day.
The objective with this sentence is too pay careful attention to its grammar construction.
The connector because in this case is a subordinating linker which means that it is connecting a subordinate clause to an independent one and the comma is not necessary.  
 
        
             
        
        
        
Answer:
The third option, "His books, in my opinion, are so similar that it's difficult to distinguish one plot from the other." Is the correct answer.
Explanation:
This sentence has an appositive and the commas are being used correctly. 
<h3>An appositive is basically a noun or a noun phrase that further identifies another noun right next to it. </h3><h2>
Rule of thumb:</h2>
- Use commas around an appositive when it is <em>NOT</em> essential to the sentence or information.
 - One word appositivies <u>(generally)</u> don't need commas.
 - If the appositive gives weight or meaning to a sentence, then you don't need to put it around the appositive.
 
 
        
             
        
        
        
The cat which, was white and fluffy,