**Answer:**

The correct option to complete the sentence is: "Wait here until I **call** you" (2).

Here's the explanation for the correct choice and why the other options are not suitable:

1. **Will call (1):** This option implies a future action, suggesting that the person speaking plans to call at some point in the future. However, the use of "until" indicates that the action is expected to happen before a certain time or event. Therefore, the present tense is more appropriate in this context.

2. **Call (2):** This option uses the present tense, which is suitable for the sentence structure and conveys that the action will happen soon. It implies that the speaker intends to make a call in the near future and is asking the person to wait until they do so.

3. **Am calling (3):** This option uses the present continuous tense, indicating an ongoing action. However, in this context, the use of the present continuous tense doesn't fit because the action of calling is not in progress at the moment of speaking. The speaker intends to make a call in the future, not currently.

4. **Am going to call (4):** This option uses the "be going to" future form, indicating a planned action. Although it implies an intention to make a call, it does not align perfectly with the sentence structure. The use of "until" suggests that the action will happen before a certain time or event, rather than simply being planned.

In conclusion, the correct choice is "Wait here until I call you" (2) because it accurately conveys the speaker's intention to make a call in the near future and asks the listener to wait until that happens.