Solving an Exponential Growth Model

The height of a plant, $H(t)$, is measured in centimeters at time $t$ in weeks. The function $H$ is differentiable and satisfies the differential equation $\frac{dH}{dt} = kH$, where $k$ is a constant. At $t=0$, the plant’s height is 50 cm and it is growing at a rate of 15 cm per week. Which of the following is an expression for $H(t)$?