Final answer:
Option d) Chlorine (Cl) has the most negative electron affinity among the given elements, implying a strong ability to attract an additional electron.
Step-by-step explanation:
The element with the most negative electron affinity, which indicates the strongest affinity to acquire an additional electron among Al (aluminum), Si (silicon), S (sulfur), and Cl (chlorine), is chlorine (Cl). Electron affinity tends to become more negative as we move from left to right across a period and from top to bottom of a group in the periodic table. Chlorine is located in the third period and is a halogen, and halogens are known to have high electron affinities due to their desire to complete their valence electron shell, which makes Cl exceptional in its ability to gain an extra electron, releasing -346 kJ/mol of energy in the process.