You have built a simple LBO model based on the acquisition of a private, family$-$held company in Germany for $10$x EBITDA with a sale for $10$x EBITDA in Year $5.$ The deal uses Senior Bank Debt for $3$x EBITDA, $1$x EBITDA worth of Seller$$s Notes, and a $1$x EBITDA Shareholder Loan $($like Preferred Stock but with tax$-$deductible PIK Interest$).$ Currently, your firm expects to earn an $18\%$ IRR over $5$ years on this deal, but it would like to earn at least a $20\%$ IRR. Based on the model excerpt below, what is the MOST VIABLE way to boost the IRR into this range?

a$.$ Increase the Debt used to fund the deal, as the company can clearly afford more than $3$x EBITDA of Senior Bank Debt.

b$.$ Remove the Seller$$s Note and Shareholder Loan and assume $5$x Debt $/$ EBITDA for the Senior Bank Debt, as the lower interest rates will improve cash flows.

c$.$ Negotiate for lower mandatory repayments on the Senior Bank Debt in exchange for a higher interest rate, which should also improve cash flows.

d$.$ Assume that the exit multiple is higher than $10$x because of the company$$s FCF growth and improved FCF conversion over this period.