Which word in the sentence is an interjection?

Oops, I forgot that we had plans already.

A.
oops

B.
already

C.
I

D.
had

Question

Which word in the sentence is an interjection? 

Oops, I forgot that we had plans already.
  
 
 

 
 

  

  A. 
  oops   
   

 
 

  

  B. 
  already   
   

 
 

  

  C. 
  I   
   

 
 

  

  D. 
  had

anonymous · Answer

an interjection is any member of a class of words expressing emotion, distinguished in most languages by their use in grammatical isolation, as Hey! Oh! Ouch! Ugh!

so, by that definition, which do you think it is?