**Answer:**

**Introduction:**
In the given sentence, we need to choose the correct form of the verb "supply" to complete the sentence correctly. The correct choice between "supplied" and "supplyed" will depend on the rules of verb conjugation.

**Explanation:**

**1. Verb Conjugation:**
- In English grammar, verbs change forms to show different tenses, moods, voices, and aspects.
- One such form is the past participle form, which is used to form the passive voice and perfect tenses.
- To form the past participle of regular verbs, we often add "-ed" or "-d" to the base form of the verb.

**2. Base Form and Past Participle of "Supply":**
- The base form of the verb "supply" is "supply".
- The past participle of the verb "supply" is "supplied".

**3. Sentence Analysis:**
- In the given sentence, "Can you have it ______________by 4:00 pm", we are looking for a verb form that can be used after "have".
- When "have" is used in the sense of causing something to be done or arranging for something to be done, it is followed by the past participle form of the verb.
- In this case, we need to use the past participle form of the verb "supply" to complete the sentence correctly.

**4. Correct Answer:**
- The correct choice for the given sentence is option 'A' - "supplied".
- The sentence should be completed as "Can you have it supplied by 4:00 pm?"

**Conclusion:**
The correct choice in the given sentence is option 'A' - "supplied". This choice follows the rules of verb conjugation and forms a grammatically correct sentence.