Without bile, the dog would have trouble digesting which type of nutrient? a. cellulose b. carbohydrates c. proteins d. lipids

Bile breaks down fats aiding in the digestion of them. 
The bile acids dissolve the fat into the watery contents of the intestinal tract. Once dissolved the fat then is digested more by enzymes produced in the pancreas and the lining of the intestinal tract. 
Hope this helps you!

It's A. Cellulose. I hope this helps you out!