I assume you are already familiar with the IUPAC rules. I will be referring to the rule number where applicable. If you do not have a copy of the IUPAC rules, please let me know by a comment or PM.
Alkane (A)
The first one is tricky, because the longest straight chain is not as drawn, but along a "branch". See first image.
Since there are 10 carbon atoms in the longest chain, the parent chain will be named decane.
The first substituent occurs in C3, that explains why the parent chain is named from right to left.
Now the substituents:
C3 : Cl and CH3, so 3-chloro 3-methyl
C6 : The Y-shape is named isopropyl, so 6-isopropyl
C7 : Substituent is a straight chain with 2 carbon atoms, so 7-ethyl
The complete name is therefore
3-chloro-7-ethyl-3-methyl-6-isopropyl-decane
Note that order is according to alphabetic order of the substituent name without the prefixes (explains why isopropyl comes after methyl)
Alkane (B)
Again, first step is to look for the longest chain, which is 11 (undecane), as numbered in image 2.
Numbering starts from the 2,2-dichloro end because it gives the lowest number for the locant.
C2 2,2-dichloro (2 branches, each is Cl)
C4 4-methyl (1 carbon atom)C5 5-ethyl (2 carbon atoms)
C8 8-ethyl
C9 9-methyl
So the complete name is
2-2-dichloro-5,8-diethyl-4,9-dimethyl-undecane
Alkane (C)
Here there are 9 carbon atoms (nonane) in the longest chain.
The locants of substituents are identical from either end. Here I choose the one with the smaller number of the first substitutent 2-methyl instead of 2,2-dimethyl, resulting the numbering starting from the right. I hope I am right here.
C2 1-methyl
C3 1-methyl
C4 1-methyl
C5 1-methyl
C6 6-fluro-6-iodo
C7 1-methyl
C8 8,8-dimethyl
So the complete name becomes
6-fluoro-6-iodo-2,3,4,5,7,8,8-heptamethyl nonane
To @study77 and anyone reading this answer:
Please check and understand everything I did in case I slipped somewhere. Any suggestion for improvement or corrections will be most appreciated.