C. Find all machines at the Almaden plant. A. Find all employees at the plant that contains machine number 1130. b. Find all employees at plants that contain machines whose type is “milling machine.” Describe a good strategy for processing each of the following queries. A. Find all employees at the plant that contains machine number 1130. b. Find all employees at plants that contain machines whose type is “milling machine.” C. Find all machines at the Almaden plant. D. Find employee 1 machine. 19.19 For each of the strategies of Exercise 19.18, state how your choice of a strategy depends on: a. The site at which the query was entered b. The site at which the result is desired 19.20 Compute r 19.21 Is ri n rj necessarily equal to rj rj = rj n ri hold?