Final Answer:
The most recently constructed reservoir, as indicated in the text, is c) 2010, Lake Houston.
Step-by-step explanation:
In the text, it is explicitly stated that Lake Houston was constructed in 2010, making it the most recently built reservoir among the options provided. The year of construction serves as a clear chronological indicator, and in this case, 2010 is the most recent among the listed options.
Lake Powell (option a) was constructed in 1963, Lake Travis (option b) in 1942, and Lake Buchanan (option d) in the 1930s. Therefore, the only reservoir that aligns with the requirement of being the most recently constructed, according to the information provided, is Lake Houston in 2010. The other options predate Lake Houston and are, therefore, not the most recent constructions.
In summary, the choice of c) 2010, Lake Houston is supported by the explicitly mentioned information in the text, which indicates the year of construction for each reservoir, allowing for a clear identification of the most recently constructed reservoir.