They are asking you what they should spend on; you say: “Whatever you are spending from the good, then it is for the parents, close relatives, orphans, needy and wayfarer. And whatever you are doing from good, then indeed Lord Allah knows with it.
This verse is revealed before the revelation of verse 9: 60 which teaches the eight categories of people who deserve the welfare tax. “Whatever you are spending from the good” mentioned in verse means whatever is earning or spending, it should be according to the dos and don’ts of Adhikr. It is told in verse 22: 77: “Oh, you who believed! You bow down, you prostrate, you serve your Lord and you do good deeds, so that you may become prosperous”. Since there is no group of believers anywhere in the world, the odd believer should spend all his bestowed blessings for propagating Adhikr which is the Balance and trust to keep the universe in its equilibrium. See explanation 2: 107, 148, and 177.