Which of the statements below are correct regarding current R&D accounting under US GAAP?

a$.$

Internally developed R&D that is incurred after technical feasibility could be capitalized

b$.$

R&D accounting results in understatement of price$-$to$-$book ratios for technology companies

c$.$

Purchased R&D is capitalized at the price paid for the purchase

d$.$

$($a$)$ and $($c$)$ above

e$.$

$($b$)$ and $($c$)$ above