Here it says which of the following represents A chalcogen with the greatest effective nuclear charge. Remember, a chalcogen is an element that is in Group 6A. So what we have to do here is figure out which element or elements are in Group 6A.
If we take a look, we have chlorine, lithium, sulfur, tellurium, and neon. The only elements from this list that are in Group 6A are sulfur and tellurium. Remember the general trend is as we head towards the top right corner of the periodic table, effective nuclear charge is going to increase.
So here we have sulfur which is in Group 6A. Below it, a few spaces below it is tellurium. So based on this trend, as we move up, a group effective nuclear charge should increase. That would mean that sulfur would be the chalcogen with the greatest effective nuclear charge from the options provided.