Final answer:
Filiforms are medical devices used in urology to bypass urethral obstruction by gently dilating the urethra. Hence, option A is correct.
Step-by-step explanation:
Filiforms are medical devices used in the field of urology. They are long, slender instruments inserted into the urethra to help bypass urethral obstruction. Filiforms are commonly used when a patient is experiencing difficulty passing urine due to a blockage in the urethra.
For example, in cases of urethral strictures or narrowing of the urethra, filiforms can be used to gently dilate the area and allow urine to flow more freely. The filiform is first inserted and guided through the obstruction, and then larger dilators are used to gradually widen the passage.