In regards to the passage, which of the following statements BEST\u00A0answers when bearded irises bloom?

This is found in the first sentence of the second paragraph. You can eliminate \u201Conly during the months that they are planted,\u201D as the passage does not state or imply this. It is true that they have to have full sun to bloom, but that does not answer when they bloom. Irises do bloom from April to June, but that also depends on what varieties are planted, as some varieties can rebloom after the summer resting period.