a.lf Jane were to pass away first, what is her tax liability before the marital deduction? b.If John were to pass away first, what is his tax liability before the marital deduction? c.Using the portable estate exemption, how much of their combined estate is taxable today? d.If Jane and John fail to take advantage of the portable estate exemption by forgetting to file IRS Form 706 at the death of the first spouse, will there be a tax liability this year, assuming the second spouse also passes shortly thereafter? Describe an estate planning strategy that can be used to minimize any estate tax liability in this situation