In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?

The most proximate reasons for the lack of cyclone formation in the South Atlantic are sea surface temperatures that tend to run a shade cooler than ideal for tropical cyclone formation even in the southern summer, climatologically high values of vertical wind shear across that basin throughout the year, and a lack of pre-existing centers of rotation (vorticity) in that area.

This last point is due both to the absence of tropical waves similar to those generated over west Africa in the northern hemisphere and to the fact the the Intertropical Convergence Zone (ITZC), which shifts toward the north in our summer and toward the south in the southern summer, usually stays at or north of the equator.

Though many people might speculate that the sea surface temperatures are too cold, the primary reasons that the South Atlantic Ocean gets few tropical cyclones are that the tropospheric (near surface to 200mb) vertical wind shear is much too strong and there is typically no inter-tropical convergence zone (ITCZ) over the ocean. Without an ITCZ to provide synoptic vorticity and convergence (i.e. large scale spin and thunderstorm activity) as well as having strong wind shear, it becomes very difficult to nearly impossible to have genesis of tropical cyclones.

So, ITCZ stays at or near the equator and does not shift southward over the south Atlantic or south Pacific region. Therefore, these regions do not have the ITCZ over them which is a major cause of lack of cyclone. While lower sea temperatures is also a cause, absence of ITCZ is the major cause, so the correct answer is b.