Explanation: Labor unions, whose workers are organized and act collectively, fought for better wages, hours, and working conditions in the 1800s and 1900s. Guilds were medieval organizations and therefore are out of the time period (A). Joint-stock companies allowed investors to purchase shares in a business. They did not advocate for workers (B). Zaibatsu groups are Japanese industrial conglomerates that controlled parts of Japan’s economy in the late 1800s and early 1900s. This answer in incorrect because they did not support improved conditions for workers and because it relates to a different region (D).