Here are some quotes of the USD: CHF dollar spot exchange rate given simultaneously on the phone, if you were trading USD for CHF, which quote is the best quote:
A. Bank A: 1.3435 - 1.3440
B. Bank B: 1.3440 - 1.3445
C. Bank C: 1.3433 - 1.3450
D. Bank D: 1.3430 – 1.3360