user: Question: What is the c (nf/km) when the r (ω/km) is 463.59?
Columns: ['Frequency (Hz)', 'R (Ω/km)', 'L (mH/km)', 'G (μS/km)', 'C (nF/km)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1', '172.24', '0.6129', '0.000', '51.57']
SQL:

assistant: SELECT "C (nF/km)" FROM "Table" WHERE "R (Ω/km)" = '463.59';