The correct option is C Adjective Clause
A clause is a part of a larger sentence containing a subject and a predicate of its own.
A Principal Clause is an independent clause which can exist even without a subordinate clause. A Subordinate Clause is called a dependent clause because it cannot exist without the help of the principal clause. It begins with a subordinating conjunction.
In this sentence, 'It is a long lane' is the principal clause and "that has no turning' is the subordinate clause. The subordinate clause qualifies the subject 'a long lane' in the principal clause thereby acting as an adjective. Hence, its a subordinate adjective clause.
So, option B becomes correct and the other options cancel out.