* I can hardly buy a new car the high price of cars in Egypt A. on account of
B. supposing
C. whereas
D. in case

A. on account of

Explanation:

Considering the structure and form of the sentence given, we can easily deduce that the speaker couldn't afford to buy a car. And this is because of the high prices of cars in Egypt.

Now, as the sentence is a cause and effect form of a sentence, the given options except option A are unrelated to be used. But on the other hand, the phrase "on account of" is the same as saying "because of" which presents a reason for why the car couldn't be bought. The other options do not present this same function.

So, the correct sentence will be

"I can hardly buy a new car on account of the high price of cars in Egypt".