In this question on changing from Active to Passive Voice, choose the option that correctly expresses the sentence "The checker checks the admission tickets at the gate" in the passive form.

Introduction / Context:
This item checks your ability to convert a simple present tense sentence from the active voice into the passive voice. The sentence describes a routine action at a gate where a checker examines admission tickets. In such questions, the examiner wants to see whether you can preserve the tense, meaning, and basic word order while correctly changing the grammatical focus from the subject to the object. Because the action happens regularly, the tense is simple present, and the passive form must also be in simple present. The correct answer will therefore use are checked along with the appropriate agent phrase.

Given Data / Assumptions:
The important points in the sentence can be listed as follows.

• Original sentence: The checker checks the admission tickets at the gate.
• Tense: simple present (checks).
• Subject: the checker.
• Object: the admission tickets.
• Adverbial of place: at the gate.

Concept / Approach:
To form the passive voice from an active sentence, the object of the active sentence becomes the subject of the passive sentence. The main verb is changed into the correct form of be plus the past participle, and the original subject is usually introduced with by. In simple present tense, the be form is am, is, or are depending on the new subject. Here the new subject admission tickets is plural, so we must use are. The main verb checks becomes checked as a past participle. Finally, we keep the adverbial phrase at the gate and add the agent phrase by the checker to show who performs the action.

Step-by-Step Solution:

Verification / Alternative check:
To verify, convert the passive sentence The admission tickets are checked at the gate by the checker back into active voice. The new subject becomes the checker, the verb becomes checks, and the object becomes the admission tickets, followed by at the gate. We arrive at The checker checks the admission tickets at the gate, which is exactly the original sentence. This confirms that tense, agent, and place have all been preserved correctly. Any option that changes the tense or removes essential information is unsuitable.

Why Other Options Are Wrong:
Option B omits the agent the checker, which makes the sentence less complete, especially in an examination context where a full transformation is usually preferred. Option C uses will be checked, which changes the tense to simple future and therefore does not match the original simple present. Option D uses were checked, which is simple past and again changes the time reference. Option E uses have been checked, which is present perfect tense and suggests completion rather than a regular action. Only option A maintains the simple present tense and includes both the agent and the place phrase correctly.

Common Pitfalls:
In voice transformation questions, students often ignore the tense and select any grammatically correct passive structure. However, correctness here means preserving tense as well as meaning. Another typical mistake is to forget the agent phrase when it is important to show who carries out the action. Learners also sometimes use wrong be forms such as is with plural subjects. Always check the number of the new subject and match it with the correct auxiliary. Then verify by mentally reversing the passive sentence back into the active one to see whether you recover the original statement.

Final Answer:
The correct passive sentence is: The admission tickets are checked at the gate by the checker.