Directions: Four parts of the sentences given below have been underlined. Identify the part having an error. If no part has an error, mark (E).

Since rats are (A) destructive and (B) may carry disease, (C) therefore many cities try to (D) exterminate them. (E) No error

The sentence contains a grammatical error with redundant causality. 'Since' already establishes a cause-effect relationship, making 'therefore' unnecessary and incorrect. The correct structure would be either 'Since rats are destructive and may carry disease, many cities try to exterminate them' or 'Rats are destructive and may carry disease; therefore many cities try to exterminate them.'