Which stage of venture capital financing is usually characterized as the period in which the capital is used for product development and marketing（）

A. Seed Stage.

B. First stage.

C. Start-up Stage.

下列实例中，属于内能转化为机械能的是（　　）

A．古代入钻木取火

B．发电机发电

C．电动机转动

D．运载火箭点火升空