Question

Two planes intersect in exactly one point.
a. always
b. sometimes
c. never

Answer 1

Planes DO NOT intersect at a point EVER. 
Planes intersect at a line. Therefore the answer is NEVER. 

Answer 2

Answer:

Option c - never

Step-by-step explanation:

Given : Two planes intersect in exactly one point.

Solution : Two planes never intersect in exactly one point.

Because, If two planes intersect, then their intersection is a line.

and a line consist of two points.

As shown in the figure attached.

There are two planes G and H and their intersection is a line l.

And the line l consist of two points.

Therefore, Option c is correct - Never