Sixteen thousand volunteers are registered with a charitable trust. In every six months the number of volunteers increases at the rate of 5 %. The time period, at the end of which the total number of volunteers becomes 18522, is ________

• A. \[2\frac{1}{2}\]years
• B. \[1\frac{1}{2}\]years
• C. \[3\frac{1}{2}\]years
• D. 3 years
• E. None of these