Today's supply curve for gasoline could shift in response to a change in a. today's price of gasoline. b. the expected future price of gasoline. c. the number of buyers of gasoline. d. All of the above are correct.

d. All of the above are correct.

Explanation:

The supply of a product represents the amount for a product a manufacturer is willing to sell at the market at a particular price at a point in time. Since manufacturers are primarily profit-focused, the supply of a product is influenced by the price of that product as well as the demand for the product.

Hence, a manufacturer can vary the amount of product supplied to the market  depending on the short term price and long term price projection as well as the demand for that product.

The correct option is d.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.