The answer is the second one (B): osteomalacia.
Explanation for each option:
A. Kidney stones - Incorrect. Kidney stones are not directly associated with insufficient vitamin D. They are more commonly related to factors such as dehydration, dietary choices, and certain medical conditions.
B. Osteomalacia - Correct. Osteomalacia is a condition characterized by the softening of the bones due to insufficient vitamin D in adults. This vitamin is crucial for calcium absorption, and its deficiency can lead to weakened bones.
C. Rickets - Incorrect. Rickets is a condition that affects bone development in children, not adults. It is also caused by vitamin D deficiency but is not applicable to adults.
D. Hypocalcemia - Incorrect. While vitamin D deficiency can lead to low calcium levels (hypocalcemia), the condition more directly associated with insufficient vitamin D in adults is osteomalacia.
In summary, insufficient vitamin D during adulthood is primarily associated with osteomalacia.