4. Which of the following statements is true about aquaculture?
A. An aquaculturist can throw some young shrimp in a pond, and they will take care of themselves
B. It means "cultivating small acreages of land."
C. An aquaculturist must tend to the tanks carefully to make sure predators do not eat the shrimp.
D. The tanks are large aquariums built in warehouses

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

i think it's letter a.