Stack effect? I'm not totally sure about this...
Explanation:
Large amount of tiny particles of water droplets, dust and smoke are present on a misty day. These tiny particles in the air scatter blue colour of white light passing through it. When this scattered light reaches our eyes, the smoke appears blue.
Answer: The correct option is A.
Explanation: The given molecules are the molecules of same element.
These molecules are considered as diatomic species.
Polar molecules are the molecules in which some polarity is present in the bond. These molecules are formed when there is some difference in the electronegativities of the elements. Example: HCl
Non-polar molecules are the molecules where no polarity is present in the bond. These molecules are formed when there is no difference in the electronegativities of the elements. Example: 
The given molecules are non-polar in nature.
Hence, these molecules must be non-polar. So, the correct option is A.
<span>Molecular compounds, which are represented by molecules, are usually made of non-metals only (or of metalloids and non-metals). Ionic compounds, which are represented by formula units, are made of metals and non-metals.
More detail if you're interested: Molecules and formula units are the representative particles for molecular and ionic compounds, respectively. By that I mean, one unit of a molecular compound is a molecule...a bundle of atoms covalently bonded that exists separately from all the other molecules. One unit of an ionic compound is a formula unit. A formula unit is a representation of the compound's formula. For example, the formula unit of NaCl is one Na^+1 ion and one Cl^-1 ion. The formula unit of AlCl3 is one Al^+3 ion and three Cl^-1 ions. Ionic compounds don't have separate bundles of atoms like molecular compounds do, so the formula unit is just the smallest number of ions that it takes to represent the formula. </span>
