Which of the following statements about organic chemistry is correct? be careful, there may only be one word incorrect.
a. organic compounds only contain carbon and hydrogen.
b. in a condensed structural formula, each carbon atom and its attached hydrogen atoms are written as a group in linear form.
c. alkanes are a type of organic compound that have at least one multiple bond between two carbon atoms.
d. the different arrangements of alkanes, known as conformations, are the three-dimensional rotation around the double bond.

In "condensed structural formula" each carbon atom and its attached hydrogen atoms are written in group in the linear form is correct about organic chemistry.

Option B

Explanation:

"condensed structural formula" is a method of writing or presenting organic structures in line of text. It presents all the atoms, but excludes the vertical bonds and all the horizontal single bonds. In condensed structural formula, or we can say semi-structural formula, covalent bonds are not always presented or shown. When the formula or representation is written in line with covalent bonds being shown, then it is referred to as linear formula. For example- the condensed structural formulas of ethane, propane, and ethanol is written as follows:-  

Apart from these Statement, all others are false because they do not have any logic with respect to organic chemistry.

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.