The moon takes approximately 27.3 days to orbit the Earth once. Therefore, in 30 days, it will orbit the Earth approximately 30 / 27.3 = 1.0989 times.

The distance covered by the moon in one orbit is the circumference of the moon's orbit, which can be calculated as 2 × π × the moon's average distance from the Earth. The average distance from the Earth is about 238,855 miles.

Therefore, the distance covered by the moon in one orbit is:

2 × π × 238,855 miles = 1,499,701.6 miles (rounded to the nearest tenth)

Multiplying this by the number of orbits in 30 days gives:

1.0989 × 1,499,701.6 miles = 1,648,983.8 miles (rounded to the nearest tenth)

Therefore, the closest option to the distance covered by the moon in 30 days is (C) 1600000 miles.