56) Randolph is a 30 percent partner in the RD Partnership. On January 1, RD distributes $15,000 cash, an investment with a fair value of $20,000 (inside basis of $10,000), and a parcel of land with a fair value of $10,000 (inside basis of $5,000) to Randolph in complete liquidation of his interest. RD has no liabilities at the date of the distribution. Randolph's basis in his RD Partnership interest is $48,000. What is Randolph's basis in the distributed investment and land?

A) $10,000 investment, $5,000 land.

B) $22,000 investment, $11,000 land.

C) $20,000 investment, $10,000 land.

D) $20,000 investment, $13,000 land.

the answer is B, but why ? i need detail calculation please

step1. 15000+10000+5000 =30000

step 2. 48000-30000=8000 remain basis how to do allocate it? and how to do the further steps?