The answer is: The flowers in the garden bloom beautifully.
The verb to be can be conjugated as am, is, are, was, were or been, and it signifies to exist, occur o take place. In that respect, the chosen sentence does not possess the verb to be - it actually contains the verb bloom, which means to produce flowers.
The rest of the sentences are incorrect because all of them include conjugations of the verb to be, such as is and was.
