Susan owns $60\%$ of the stock of a corporation, and her brother owns the remaining $40\%.$ The corporation owns a life insurance policy on Susan's life the beneficiary of which is her husband.

$($a$)$ Will the policy proceeds be included in Susan's gross estate?

$($b$)$ Same as $($a$),$ but the corporation is the beneficiary of the policy.

$($c$)$ Same as $($a$),$ except the corporation transferred the policy to an irrevocable trust for the benefit of Susan's husband $2$ years prior to her death.

$($d$)$ Same as $($a$),$ except Susan transferred a $20\%$ interest in the corporation to her husband $5$ years before her death.

$($e$)$ Same as $($d$),$ but the entity is an LLC instead of corporation.