PQ is a chord of length 8 cm, of a circle with centre O and of radius 5 cm. The tangents at P and Q intersect at a point T. The length of TP is

• A. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>20</center></td><td rowspan="2"> cm.</td></tr><tr><td style="text-align: center;">3</td></tr></table>
• B.
• C. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>21</center></td><td rowspan="2"> cm.</td></tr><tr><td style="text-align: center;">4</td></tr></table>
• D. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>10</center></td><td rowspan="2"> cm.</td></tr><tr><td style="text-align: center;">3</td></tr></table>
• E. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>15</center></td><td rowspan="2"> cm.</td></tr><tr><td style="text-align: center;">4</td></tr></table>