What the us census is completed each state is notified how its population affects its number of congressional district. this process is called

Congress has delegated responsibility for taking the census to the Department of Commerce and its Bureau of the Census in Title 13 of the United States Code. The law directs the secretary of commerce to “take a decennial census of population as of the first day of April . . . the ‘decennial census date’” in 1980, 1990, 2000, etc. The secretary must complete the census and report the total population, by states, to the president by December 31 of the census year. The purpose of the report is “the apportionment of Representatives in Congress among the several States” as required by Article I, Section 2, of the U.S. Constitution. 

When the Congress convenes in 2001, the president must transmit to that body a statement of the apportionment of the 435 representatives’ seats among the states. The number of representatives allocated to each state is based on the census results and determined by the “method of equal proportions.” Each state is guaranteed at least one representative, and the remaining 385 seats are apportioned among the states by assigning priority values to each seat. 

Title 13, as amended by Public Law 94-171 (1975), also requires the secretary of commerce to report census results no later than April 1, 2001, to the bodies or officials charged with state legislative redistricting and to the governors. These reports contain the population data for various geographical areas within the state, including the smallest areas, the “census blocks.” The April 1 reports provide the basis for state and local level decennial redistricting efforts as well as for the redrawing of congressional districts within each state.  Figure 1 explains the three-phase process by which the Census Bureau plans to gather and distribute this redistricting data by the April 1 deadline.

if i am correct the answer is going to be a) the federal program of reconstruction ended.