Select the noun phrase to complete the sentence. the flowers bloom every year in april (pictures are my choices)

There is only one noun phrase in the picture. That is, your answer would be "dark purple irises". "Slowly but surely" is not a noun phrase, but an adverbial phrase and "with the purple petals" is a prepositional phrase.

In this way, the complete sentence would be as follows: The flowers, dark purple irises, bloom every year in April. This NP is an apposition as the two nouns refer to the same thing (flowers/irises) and are placed immediatly after the other with no conjunction between them.

d.) then bernice winced as marjorie tossed her own hair over her shoulders and began to twist it slowly into two long blond braids until in her cream-colored negligée she looked like a delicate painting of some saxon princess. fascinated, bernice watched the braids grow. heavy and luxurious they were, moving under the supple fingers like restive snakes—and to bernice remained this relic and the curling iron and a to-morrow full of eyes.

i think it is called the president's cabinet.