The correct option is A PS1
The chlorophyll a and the accessory pigments form the photosystem. There are two photosystems (PS1 and PS2). The photosystems varies in the wavelength of light that they absorb.
Photosystem 1 (PS1) absorbs light of wavelength 700nm, while photosystem 2 (PS2) absorbs light of wavelength 680nm. The photosystems are present in the chloroplast. The membrane of thylakoids or the grana lamellae has both PS1 and PS2. But the stroma lamellae lacks PS2 and has only PS1.