Explanation:

- The word "replaced" means to take the place of something or someone with another, implying a substitution.

- Option 1: Removed - This means to take something away or off. It doesn't necessarily imply a substitution.

- Option 2: Moved - This means to change the position of something. It doesn't imply taking something's place.

- Option 3: Instituted - This means to establish or introduce something new. It can imply creation rather than substitution.

- Option 4: Substituted - This means to put something new in the place of something else, essentially taking its place.

Correct Answer: Option 4 is indeed the synonym for "replaced".