Insulin shots???

I’m 36 weeks pregnant and I have been taking insulin shots on my thigh as per my OBG-YN but today I went to see maternal fetal medicine(MFM) doctor and he said I supposed to take it on my tummy since it’s more effective that way. I got pregnant through FET and that’s the reason I have to go to MFM docs. Also my doctor said I have to get c section done due to GD and low placenta but today MFM said I have to go natural because my placenta has been moved and GD is not the reason for C Section. I’m confused now that I don’t know who to trust. Who to follow? Please give me suggestions what did you or your doctor suggested if you had GD? Natural or C section? Insulin on thigh or stomach?