What is the most common causal pathogen of UTIs?

I- Escherichia Coli (E-Coli) is the most common causal pathogen of UTIs.
II- Proteus spp. is the most common causal pathogen of UTIs.
III- Klebsiela spp. is the most common causal pathogen of UTIs.
a) Only I is correct.
b) Only II is correct.
c) Only III is correct.
d) I and II are correct.
e) I and III are correct.