MathDB

In rectangular coordinate system, define that if and only if both

x

-axis and

y

-axis of a point are integers, we call it itegral point.

I

is set of all lines,

M

is set of lines that pass exactly one intengral point,

N

is set of lines that pass no itengral point,

P

is set of lines that pass infinitely many itengral points. Then, how many conclusions are right? (1)

M\cup N\cup P=I

. (2)

N\neq\varnothing

. (3)

M\neq\varnothing

. (4)

P\neq\varnothing

\text{(A)}1\qquad\text{(B)}2\qquad\text{(C)}3\qquad\text{(D)}4\qquad

Problem Statement