The correct passive form of the given sentence is:

☀ The prices are displayed by the new company.

Let's break down the options:

1. The prices displayed by the new company. (Incorrect) This option is in the passive voice and mentions "the prices" as the subject, which is correct. However, it lacks the verb "to be" in the passive form, making it an incomplete passive construction.

2. The prices are displayed by the new company. (Correct) This sentence correctly uses the passive voice and conveys the same meaning as the original sentence. It uses the correct form "are displayed."

3. The prices was displayed by the new company. (Incorrect) This option uses the incorrect verb form "was displayed." The subject "the prices" is plural, so the correct form should be "were displayed." However, the original sentence uses the present tense "announces," so the correct passive form should be in the present tense as shown in option 2.

4. The new company got down the prices. (Incorrect) This option changes the meaning of the original sentence. It suggests that the new company reduced the prices, but the original sentence is about the company announcing the prices, not changing them. The correct passive form should focus on the prices being displayed, not changed.