The correct answer is (B) 7 .

Here is the step-by-step explanation for how to find the maximum number of parts.
1. Start with the circle: A single, uncut circular region is 1 part.
2. Add the first line: The first line, which must pass through the circle and intersect the circumference at two points, divides the circular region into 2 parts.
3. Add the second line: To get the maximum number of parts, the second line must intersect the first line inside the circle. This adds 2 new parts.
Total parts $=2($ from the first line $)+2($ from the second line $)=4$ parts .
4. Add the third line: To get the maximum number of parts, the third line must intersect both of the previous lines inside the circle. Each intersection point adds a new segment to the line, and each segment creates a new region. With two intersections, this line is divided into three segments and therefore adds 3 new parts.
Total parts $=4$ (from the first two lines) +3 (from the third line) $=7$ parts.
To maximize the number of regions, each new line must intersect all of the existing lines. The number of new regions added by each subsequent line is equal to the number of lines already in the circle, plus one.

- 1 line: $1+1=2$ regions
- 2 lines: $2+2=4$ regions
- 3 lines: $4+3=7$ regions