Obviously no picture here, but "A" in the picture represents Broca's area, which would cause the expressive aphasia this patient is experiencing.
However, the question also states the patient has weakness of the lower two-thirds of his face. This may cause you to think there is maybe a lesion in the pre-central motor area (thinking humonculus), but realize that the motor area travels all the way down to the bottom of the frontal lobe, RIGHT BEHIND THE BROCA'S AREA. In fact, Broca's area encompasses that part of the humonculus. And since the upper part of the face is controlled by the upper part of the facial motor cortex, and the lower part is controlled by the lower part of the facial motor cortex, you can have paralysis of the lower part of the face and have expressive aphasia if the lesion is in that specific area (does not need to be a lower motor lesion to spare the upper face/forehead).