Answer:
D. Enact measures to test city pools more frequently.
Step-by-step explanation:
Giardiasis is an infection in the small intestine caused by the protozoan Giardia. Infection occurs primarily when a person eats protozoan cysts (the way the parasite acquires to withstand unfavorable environmental conditions until it reaches a host) present in faeces-contaminated food and untreated water. Because of this form of transmission, it is very important to have clean food ingested by the community and proper water treatment, so Tia can help prevent her community from preventing the spread of the disease by taking measures to test urban settings with more often.