**Problem**

The number of hours daylight, *D*(*t*) at a particular time of the year can be approximated by

$D(t) = \dfrac{K}{2}\sin \left[ \dfrac{2\pi}{365}(t - 79) \right] + 12$

for *t* days and *t* = 0 corresponding to January 1. The constant *K* determines the total variation in day length and depends on the latitude of the locale. When is the day length the longest, assuming that it is NOT a leap year?

A. December 20 |
C. June 20 |

B. June 19 |
D. December 19 |

**Answer Key**