Information from the left visual field enters the left visual cortex via the a. optic chiasm b. anterior commissure c. superior colliculus d. corpus callosum

I believe the most appropriate answer is a. optic chiasm

From retina, the optic nerve will go to optic chiasm where it will go to the lateral geniculate nucleus and medial colliculus. Medial colliculus will go to the superior colliculus, while lateral geniculate nucleus goes to the visual cortex.
Optic nerve is decussating/crossing at the optic chiasm, not the corpus callosum. Anterior commissure also irrelevant to the visual tract.

answer: - b cells

explanation: -

there are many types of white blood cells present in our body. one such class of white blood cells are the lymphocytes. the b cells belong to the lymphocyte class of wbcs. the b cells perform their action against the pathogen by producing specialised proteins called as antibodies. these antibodies are produced as and when the b cells encounter pathogens in response to the antigens present on the surface of the pathogen. these antibodies bind to the antigens present on the pathogen and then, target them for destruction by other cells of the immune system.

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.