Answer: Option (d) is the correct answer.
Step-by-step explanation:
The amount of energy released when an electron is added to a neutral atom or ion preset in gaseous phase to form a negative ion then it is known as electron affinity.
As we move across a period, due to the decrease in size of atom there will be increase in electron affinity. And, when we move down a group then there will be decrease in electron affinity.
More positive is the value of electron affinity more readily the atom can gain an electron. And, more negative value of electron affinity means atom will have difficulty in gaining an electron.
Thus, we can conclude that the statement it tends to be more negative down a group correctly summarizes the trend in electron affinity.