In a floating exchange rate system, the value of a currency is determined by the market forces of supply and demand, including various factors influencing the relative supply and demand of currencies. Let's examine each option:

(A) Floating exchange rate is determined by the supply and demand of Dollar only. This is not accurate, as the value of a currency is influenced by a variety of factors beyond just the supply and demand of a single currency.

(B) Floating exchange rate is determined by the supply of the particular currency. While the supply of a specific currency is a factor, it is not the sole determinant of a floating exchange rate.

(C) Floating exchange rate is determined by the total stock of gold reserves. This is not accurate, as a country's gold reserves are not directly tied to the determination of the value of its currency in a floating exchange rate system.

(D) Floating exchange rate is determined by the demand for the particular currency. While the demand for a specific currency is a relevant factor, it is not the sole determinant of a floating exchange rate.

(E) Floating exchange rate is determined by the relative supply and demand of the currencies. This is the most accurate description, as it considers the interaction between the supply and demand of different currencies, which collectively influence the floating exchange rate.

Based on the analysis, the correct answer is (E) Only.