Pigment-containing membranous extensions in some cyanobacteria are
(1) heterocysts
(2) basal bodies
(3) pneumatophores
(4) chromatophores
Some of the cyanobacteria and photosynthetic bacteria contain internal membrane systems known as chromatophores. They contain pigments used to capture light energy for the synthesis of sugars.
Hence, the correct option is (4).
