A solid right circular cone is cut into two parts at the middle of its height by a plane parallel to its base. The ratio of the volume of the smaller cone to the whole cone is:

Options

A. (A) 1:2
B. (B) 1:4
C. (C) 1:6
D. (D) 1:8

Explanation

To solve the problem, we need to find the ratio of the volume of the smaller cone to the volume of the whole cone when a solid right circular cone is cut into two parts at the middle of its height by a plane parallel to its base.

### Step-by-Step Solution:

1. **Understanding the Cone Dimensions**:
- Let the height of the original cone be \( h \).
- The radius of the base of the cone is \( r \).

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