Hot-summer Mediterranean climate : This subtype of the Mediterranean climate (Csa) is the most common form of the Mediterranean climate, therefore it is also known as a "typical Mediterranean climate".
Regions with this form of a Mediterranean climate experience average monthly temperatures in excess of 22.0 °C (71.6 °F) during its warmest month and an average in the coldest month between 18 and −3 °C (64 and 27 °F) or, in some applications, between 18 and 0 °C (64 and 32 °F).
Regions with this form of the Mediterranean climate typically experience hot, sometimes very hot and dry summers and mild, wet winters.
Namibia has a subtropical desert climate characterized by great differences in day and nighttime temperatures, low rainfall and overall low humidity.
Csa climates are mainly found around the Mediterranean Sea, southwestern Australia, southwestern South Africa, sections of Central Asia, northern sections of Iran and Iraq, the interior of northern California west of the Sierra Nevada, and inland areas of southern Oregon west of the Cascade Mountains.
Therefore, USA is the correct answer and hence, option C is the correct option.