In microwave oven, we use electromagnetic oscillators which produce electromagnetic waves in the wavelength range (A) \(1 \mathrm{~mm}\) to \(10 \mathrm{~m}\) (B) \(0.7 \mu \mathrm{m}\) to \(1 \mathrm{~mm}\) (C) \(0.1 \mathrm{~m}\) to \(1 \mathrm{~mm}\) (D) \(0.1 \mu \mathrm{m}\) to \(0.7 \mu \mathrm{m}\)

First, let's identify the range of wavelengths that belongs to the microwave category of the electromagnetic spectrum. Microwaves fall within the range of \(1 \mathrm{~mm}\) to \(100 \mathrm{~cm}\) wavelengths.

Now, let's analyze the given options and compare them to the identified microwave range we found in Step 1. (A) \(1 \mathrm{~mm}\) to \(10 \mathrm{~m}\) - This option starts in the microwave range, but it extends further out into the radio wave spectrum. (B) \(0.7 \mu \mathrm{m}\) to \(1 \mathrm{~mm}\) - This option starts in the infrared range and ends with the starting point of the microwave range. So, it doesn't cover the entire microwave range. (C) \(0.1 \mathrm{~m}\) to \(1 \mathrm{~mm}\) - This option covers the range from \(10 \mathrm{~cm}\) to \(1 \mathrm{~mm}\), which is part of the microwave range. (D) \(0.1 \mu \mathrm{m}\) to \(0.7 \mu \mathrm{m}\) - This option corresponds to the ultraviolet part of the electromagnetic spectrum, not the microwave range.

Based on our analysis in Step 2, the best answer is option (C) \(0.1 \mathrm{~m}\) to \(1 \mathrm{~mm}\), as it covers a significant portion of the microwave range, while the other options cover either a different range or only a small portion of the microwave range.