In a group of $100$ people, $40$ own a cat, $25$ own a dog and $15$ own a cat and a dog. Find the probability that a person chosen at random

a) owns a dog or a cat,

b) owns a dog or a cat, but not both

c) owns a dog, given that he owns a cat

d) does not own a cat, given that he owns a dog.

My attempt,

a) $P(\text{dog}\cup \text{cat})=0.25+0.4-0.15=0.5$

b) $P(\text{dog}\cup \text{cat})-P(\text{cat}\cap\text{dog})=0.5-0.15=0.35$

c) $P(\text{dog}\mid\text{cat})=\frac{0.15}{0.4}=0.375$

How to solve the question d?