Box 0 8.5 Another type of fuel cell uses methanol instead of hydrogen.
Figure 7 represents the reaction in this fuel cell.
Figure 7
H
2H-C-0-H + 30=0
20=C=0 + 4H-O-H
H
I
Table 4 shows the bond energies for the reaction.
Table 4
C-H
C-O
O-H
O=0
C=O
412
360
464
498
Bond energy in kJ/mol
805
Calculate the overall energy change for the reaction.
Use Figure 7 and Table 4.
[3 marks]

"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.