The correct answer is: C. 25 to 30 years.
Creosote is a wood preservative that is commonly used to protect wooden poles from decay and insect damage. It is a dark, viscous liquid that is derived from coal tar. Creosote is effective in preventing the growth of fungi and bacteria, and it also repels insects.
When creosote is applied to wood, it penetrates the surface and forms a protective barrier. This barrier helps to prevent the wood from absorbing moisture, which can lead to decay. Creosote also helps to prevent the wood from being attacked by insects.
The life of a wooden pole that is well impregnated with creosote oil or any preservative compound can be up to 25 to 30 years. This is significantly longer than the life of a wooden pole that is not treated with creosote.
The other options are incorrect because they do not accurately reflect the life of a wooden pole that is well impregnated with creosote oil or any preservative compound. Option A (2 to 5 years) is too short, and option B (10 to 15 years) is too long. Option D (60 to 70 years) is not realistic, as it is unlikely that a wooden pole would last this long without being treated with creosote.