Answer : Option C) 0.3 mol of Gold.
Explanation : Amongst the options given in the question, 0.3 mol of Au is the greatest in mass in grams.
As 0.3 mol X atomic weight of Au (196.966) = 59.088 grams;
Silver has 0.5 mol X atomic weight of Ag (107.86) = 53.93 grams;
The other options are not relevant as they deal in the atomic range which has mass value very less as compared to the moles of elements.
Therefore, it is clear that Au has the greatest mass amongst the given choices.