In $2017,$ Tesla issued a bond for the first time. It issued a $10-$year bond with $$1\mathrm{.}8$B in face value, offering a $5\mathrm{.}3\%$ coupon rate $($annual$).$ The bond was issued at par value $($i$.$e$.,$ price $=100).$ Now, due to the improvement of the firm$$s financial status, the yield has dropped to $4\mathrm{.}53\%.(1)$ What is the current price of this bond? Assume there are $5$ years to maturity, and Tesla has just made the last coupon payment. $(2)$ At the time of issuance, Tesla$$s stock price was $$350,$ and there were $167$M shares outstanding. Beta was $1\mathrm{.}4.$ The risk$-$free rate was $1\%,$ and market risk premium was $7\%.$ Assume a tax rate of $34\%$ for Tesla, and it had enough earnings to benefit from tax shield. What was its after$-$tax WACC before and after the bond issuance in $2017?(3)$ If$,$ in $2017,$ Tesla had changed the issue size to $$3$B $($also $5\mathrm{.}3\%$ coupon rate, sold at par$)$ instead of $$1\mathrm{.}8$B$,$ what would be the new cost of equity right after issuance?