Answer:
Graph a) is a Euler Path
Odd at D and F
Explanation:
A graph has an Euler circuit if and only if the degree of every vertex is even.
A graph has an Euler path if and only if there are at most two vertices with odd degree.
a) Odd at D and F - Euler Path
b) No odds - Euler Circuit
c) Odd at A, C, E, F
d) Odd at A, B, C, D