The correct answer is option 3, which is 100 mg/100 ml. Fasting blood glucose level refers to the amount of glucose in the bloodstream after a period of fasting. A fasting blood glucose level of 100 mg/100 ml is considered normal for adults.

Option 1, which is 200 mg/100 ml, is too high and indicates hyperglycemia, which is elevated blood sugar levels and may be a sign of diabetes.

Option 2, which is 160 mg/100 ml, is also above the normal range and suggests prediabetes or impaired glucose tolerance.

Option 4, which is 60 mg/100 ml, is too low and indicates hypoglycemia, which is low blood sugar levels and can be a symptom of certain medical conditions or medication side effects.

Therefore, the correct fasting blood glucose level for adults is 100 mg/100 ml.