Step 1: Understand the concepts of In-situ and Ex-situ conservation.
In-situ conservation: This method involves the conservation of species within their natural habitats or ecosystems. It focuses on protecting the entire ecosystem along with the species living in it.
Ex-situ conservation: This method involves the conservation of components of biological diversity outside their natural habitats. This typically means maintaining populations in artificial or human-controlled environments.
Step 2: Evaluate each option based on these definitions.
(A) Seed bank: A seed bank stores seeds of various plant species, often under controlled conditions (low temperature, low humidity) to maintain their viability for long periods. This is a method of conserving genetic material \textit{outside} its natural environment. Therefore, it is an Ex-situ conservation method.
(B) National Park: A National Park is a protected area of natural or semi-natural land, set aside by a sovereign state for the conservation of ecosystems, wildlife, and natural resources. Conservation efforts within a national park occur \textit{in the species' natural habitat}. Therefore, it is an In-situ conservation method.
(C) Cryopreservation: This process involves preserving biological materials (like seeds, gametes, embryos, or tissues) by cooling them to very low temperatures (e.g., in liquid nitrogen). This allows for long-term storage \textit{outside} the natural habitat. Therefore, it is an Ex-situ conservation method.
(D) Zoological park (Zoo): A zoological park is a facility where live animals are kept in enclosures, cared for, and displayed to the public. These animals are maintained \textit{outside} their natural habitat, often for breeding programs and public education. Therefore, it is an Ex-situ conservation method.
Step 3: Identify the mismatch.
The question asks to identify the option that is \textit{not} an Ex-situ conservation method. Based on the analysis, National Park is an In-situ conservation method.