If you want to leave the $$ to your kids, you should utilize the insurance/annuity product, it can turn $4 mil - $5 mil to your children/grandchildren tax free;
If you don't want to leave to your kids, you should go with some return guaranteed products including product in choice B) (but not all the $$ on one bond). Many senior bonds have similar/higher return subject to issuers' credit risk.
Sometimes investors are so focus on returen rate and forget they have to sacrefice life quality(such as lots of effort on rental property)or take too much risk (such as chasing high return stocks).