Aweight of 0.27 kilogram is
1. 0.00027 mg
2. 270 mg
3. 27 mg
4. 2.7 × 105 mg

The answer is:  4)  " 2.7 * 10⁵  mg "   .

Explanation:

Since all answer choices given are in "mg" ("milligrams");  we need to convert our given value, "0.27 kg" ("kilograms") to "mg" ("milligrams").

Note the following "exact value" conversions:

 1000 mg = 1 g ;
   1000 g = 1 kg. 

(0.27 kg) (1000 g / 1 kg) (1000 mg/1 g) = __?__ mg ;

 The units of "kg", and "g" cancel to "1" and we are left with:

0.27 * 1000 * 1000  mg  = 270,000 mg =  2.7 * 10⁵  mg ; which is:

                                                               → Answer choice: # 4  .