Bridget purchased the following shares of xyz stock:

50 shares for $1,500 in 2013.

75 shares for $2,000 in 2014.

85 shares for $2,750 in 2015.

She sold 130 shares of xyz in 2017 and did not identify which shares she sold. What basis should she use for computing gain or loss?

a) $3,662

b) $3,858

c) $3,869

d) $3,950