Multi-choice problem: Continue writing the next sentence in this paragraph:

How to diagnose gallstones
Be aware that gallstones are often asymptomatic.
Gallstones can exist without ill effects for decades. Most people experience no symptoms when they have gallstones; in fact only 5 to 10% of people develop some symptoms of gallstones.

Choose your answer from:
(a). The symptoms are less severe, but you still may have symptoms. If you are nervous about trying this method, talk to your doctor about how to be more aware of your symptoms.;
(b). However, symptoms can occur regularly for up to several years. Gallstones can also occur for several reasons: decreased appetites, arthritis, and muscle weakness.;
(c). This can make it difficult to know what to look for if you suspect you may have gallstones, and further indicates the importance of consulting a doctor for official diagnosis. Fewer than half the number of people who actually have gallstones even experience symptoms.;
(d). Gallstones are caused by too few nutrients and too little calcium in the body. Gallstones are often caused by insufficient nutrients and low amount of calcium in the body.;
(c).