Cattle Farm plc owns a heard of cows. On $30$ June $20$X$1,30$ calves were born. Given the information below, what is the fair value gain or loss

regarding the calves for the year ended $31$ December $20$X$1$ according to IAS $41$ Agriculture?

Fair value of a newly born calf at $30$ June $20$X$1$: $120$

Fair value of a $6-$month$-$old calf at $31$ December $20$X$1$: $180$

Costs to sell a newly born calf at $30$ June $20$X$1$: $5$

Cost to sell a $6-$month$-$old calf at $31$ December $20$X$1$: $10$

a$.$ A gain of $5,100$

b$.$ A gain of $5,400$

C$.$ A loss of $5,100$

d$.$ A loss of $5,400$