An objection of lack of unity of invention, if applicable, should already have been raised at the search stage. If such an objection was not raised, but the examining division nevertheless considers that the requirements of Art. 82 are not met, the question of lack of unity will be addressed as early as possible during examination.
In response to an objection of lack of unity, the applicant must clearly indicate which searched invention he wishes to prosecute further. If the response is unclear, the examining division must seek clarification before continuing with examination (see T 736/14).