Answer:
The word that creates the verb mood error is:
Was.
Explanation:
"I were" is called the subjunctive mood, and is used when you're are talking about something that isn't true or when you wish something was true.
Here in the given statement:
" If I was taller, I could reach the top shelf "
Here the word that creates the verb-mood error is:
Was.
( Since the correct grammatical form of the statement or sentence is:
" If I were a little taller; I could reach the top shelf " )