Final answer:
The nurse should instruct the patient to avoid fluids such as tea, coffee, and cola to manage stress incontinence.
Step-by-step explanation:
Stress incontinence is caused by the loss of support of the urethra, typically due to stretching of pelvic floor muscles during childbirth. It is characterized by the leakage of small amounts of urine with activities that increase abdominal pressure. To address stress incontinence, a nurse should provide the instruction to avoid fluids such as tea, coffee, and cola as they can irritate the bladder and worsen symptoms. By avoiding these fluids, the patient can minimize the risk of experiencing sudden urges to urinate. Therefore, option b, 'Avoid fluids such as tea, coffee, and cola,' is the correct instruction for a patient diagnosed with stress incontinence.