Spot the error in the following sentence and choose the appropriate option.
Democracy is the system in which people could exercise some control over their rulers.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → could
The sentence gives a definition, a general truth, in the simple present ("Democracy is the system"). The modal in the relative clause must match it: can expresses present ability or possibility, while "could" is its past form.
Option 1: is — No error. The simple present suits a definition.
Option 2: could — Error. It puts a present general truth in the past; it should be can: "in which people can exercise some control over their rulers".
Option 3: exercise — No error. "Exercise control" (use one's power) is the right verb, in the base form after a modal.
Option 4: over — No error. The noun "control" takes over: control over someone or something.
Corrected: Democracy is the system in which people can exercise some control over their rulers.
Example: A library is a place where anyone can read books free of cost.