A is a model of a decomposition reaction
Answer: The correct option is A.
Explanation: In a chemical reaction, reactants react to form a number of products.
For the formation of products, the bonds of the individual reactants must be broken and the bonds of the products must be formed.
For example: Formation of water from hydrogen gas and oxygen gas. Reaction follows:

The Bonds of hydrogen and oxygen molecule are broken and new bonds between hydrogen and oxygen atoms are formed to give water molecule.
We have to get the formula of methionine.
The formula of methionine is
Methionine is an essential amino acid of human. It is white crystalline solid.
The formula of methionine is C₅H₁₁NO₂S. Methionine contains five carbon atoms, eleven hydrogen atoms, one nitrogen atom, two oxygen atoms and one sulphur atom.
It contains one amino group (-NH₂) and one carboxylic acid group (-COOH). Atoms are depicted in C-atom in grey, H-atom in ivory, O-atom in red, N-atom in blue and S-atom in yellow.
... liquid water are two different forms of the same chemical substance, water. A chemical substance is a form of matter that has constant chemical ...
There are different formula you need to keep in mind when solving for [OH-]
Given that pH = 6.10
pH + pOH = 14
6.10 + pOH = 14
pOH = 7.9
[OH-] = 10^(-pOH)
[OH-] = 10^(-7.9)
[OH-] = 0.000000013
[OH-] = 1.3 x 10^-8
<h2>
<u>Answer: [OH-] = 1.3 x 10^-8</u></h2>