Accurate statistics with regards to the area occupied in different forms of cultivation are difficult to obtain.

The most appropriate phrase to replace the phrase given in bold is “statistics with regard to”. It is to be noted that ’Statistics’, when used as a subject, always takes a singular verb. For example, Statistics is not an easy subject. But, whenever ’statistics’ denotes some statistical facts or data, the very following it is always plural, which is the case here. Since option 2 is in the precise grammatical syntax, it becomes the most suitable answer choice.