Question $4$

Your eccentric weal thy uncle wants to donate money to you so that you can pursue your hobbies without fulltime strems, which would if given a choice betreen the following tour in $5\%$ p$.$a$.?$

$($a$)$ $$400,000$ today

$($b$)$ $$15,000$ per year forever

$($c$)$ $$30,000$ each year for the next $20$ year's

$($d$)$ $$600,000$ in $10$ years' time