In each part, either draw a graph with the given specifications or explain why no such graph exists. (a). A graph with 6 vertices that has at least two circuits, (b). A connected graph with 4 vertices...

Discrete math: In each part, either draw a graph with the given specifications or explain why no such graph exists.
(a). A graph with 6 vertices that has at least two circuits, one is Euler circuit, but no Hamiltonian circuits.
(b). A connected graph with 4 vertices that has three Hamiltonian circuits but no Euler circuits.
(c). A circuit free graph with 6 vertices and total degree 12.
(d). A binary tree to represent expression: (?−??+?∙?)∙(?÷(?−ℎ)+?).

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Extracted text: In each part, either draw a graph with the given specifications or explain why no such graph exists. (a). A graph with 6 vertices that has at least two circuits, (b). A connected graph with 4 vertices that has three one is Euler circuit, but no Hamiltonian circuits. Hamiltonian circuits but no Euler circuits. (c). A circuit free graph with 6 vertices and total degree 12. (d). A binary tree to represent expression (+ d · e)·f ÷ (g – h) + i). a-b