Final answer:
Cystitis, a type of urinary tract infection, is most commonly caused by bacterial infections, particularly Escherichia coli. Option a.
Step-by-step explanation:
The most common type or cause of cystitis is a bacterial infection. Bacteria from the GI tract, typically Escherichia coli (E. coli), reach the bladder, multiply, and create an infection. This condition is considerably more common in females due to anatomical differences, such as a shorter urethra, which is closer to the anus, making it easier for bacteria to enter the bladder. Risk factors include sexual intercourse, diabetes, obesity, and female sex. Symptoms of cystitis may include dysuria, pyuria, hematuria, and bladder pain. Treatment for bladder infections primarily involves antibiotics. Option a.