$11.$ Which of the following statements regarding intangible assets is false?

a$.$ Intangible assets have no physical characteristics.

b$.$ Research and development $($R&D$)$ costs incurred by the company are included in the cost of the intangible asset developed.

c$.$ Definite$-$life intangible assets are often amortized on a straight$-$line basis.

d$.$ Examples of intangible assets include patents, copyrights, and goodwill.