Among the given compounds, A) 
, D) RbI, E) BaO are ionic compounds.
Further Explanation:
Chemical bonds are the attractive forces that enable the formation of compounds or molecules. The compounds resulting from such bonds are chemical compounds. These bonds form due to the mutual sharing of electrons or electron transference.
Covalent bond
The chemical bond formed as a result of mutual sharing of electrons between the atoms is called the covalent bond. This bond is usually formed between two or more non-metals. It is responsible to form covalent compounds in nature.
Ionic bond
The chemical bond formed as a result of electron transfer from one atom to another is an ionic bond. It leads to the formation of ionic compounds. It involves the formation of ions. The positively charged ions or cations are formed by the loss of electrons from the atom. Anions or negatively charged ions are formed when a neutral atom gains electrons. This bond is generally formed between metals and non-metals.
Electronegativity difference 
is a key factor in predicting whether a bond is polar or nonpolar. If 
is less than 0.4, the bond is a nonpolar covalent bond. If is between 0.4 and 1.7, the bond is a polar covalent bond. If comes out to be greater than 1.7, the bond is ionic.
A)
In , chlorine is a highly electronegative element so there is an electronegativity difference in the bonded atoms in this molecule. Therefore is an ionic compound.
B) 
In , both sulfur and oxygen are nonmetals so this is a covalent bond.
C) ICl
The electronegativity of chlorine is 3.0 while that of iodine is 2.5 so their electronegativity difference in ICl comes out to be 0.5 and this molecule is a polar covalent compound.
D) RbI
Rubidium is metal while iodine is a nonmetal so the bond formed between Rb and I is an ionic bond. Therefore RbI is an ionic compound.
E) BaO
Barium is metal whereas oxygen is a nonmetal so the bond formed between Ba and O is an ionic bond. Therefore BaO is an ionic compound.
F) 
Both nitrogen and hydrogen are nonmetals so is a covalent compound.
Therefore , BaO, and RbI are ionic compounds.
Learn more:
Identification of ionic bonding:
What type of bond exists between phosphorus and chlorine?
Answer details:
Grade: High School
Chapter: Ionic and covalent compounds
Subject: Chemistry
Keywords: ionic bond, covalent bond, nitrogen, hydrogen, NH3, BaO, RbI, ICl, NH4Cl, SO2, metals, nonmetals.
