Which of the following practices did Martin Luther condemn in his works?

Martin Luther is best known for his condemnation of the selling of indulgences, a practice where the Catholic Church allowed people to pay for forgiveness of sins, often as a way to raise money for church projects. Luther argued that this practice was a corruption of the original Christian teachings, which emphasize faith and grace rather than financial transactions as a means of salvation. His famous Ninety-Five Theses, published in 1517, specifically called out the abuses related to indulgences and sought to reform the church from within, highlighting the necessity of returning to biblical principles.

The other practices listed—such as the confiscation of property by local churches, the selection process for the pope, and the corruption of kings condoned by the church—were certainly areas of concern during Luther's time and contributed to the broader Protestant Reformation, but they were not the primary focus of Luther’s early writings. His initial advocacy was specifically aimed at the practice of selling indulgences, making it the central issue he sought to address in his reformative efforts.