Question

One of the foci for the moon's orbit would be the

(1) Sun (3) Mars
(2) Earth (4) Venus

Answer 1

The question is oversimplified, and pretty sloppy.

Relative to the Earth . . .
The Moon is in an elliptical orbit around us, with a period of
27.32... days, and with the Earth at one focus of the ellipse.

Relative to the Sun . . .
The Moon is in an elliptical orbit around the Sun, with a period
of 365.24... days, and with the Sun at one focus of the ellipse,
and the Moon itself makes little dimples or squiggles in its orbit
on account of the gravitational influence of the nearby Earth.

I'm sorry if that seems complicated. You know that motion is
always relative to something, and the solar system is not simple.

Answer 2

2) Earth

Step-by-step explanation:

As per Kepler's first law we know that all planets and all satellites revolves in elliptical path with one of its focii as Sun or planet around which satellite and planets are revolving.

Now here we need to know about the focii of moon which is revolving around Earth in its elliptical path.

So as per same law we can say that since moon is revolving around the Earth so its focii must be Earth

So here correct answer would be

2) Earth