Such bad habits will led ______ disgrace

The correct answer is to. The phrase 'led to' is a standard English collocation meaning resulted in or caused. In the sentence, 'Such bad habits will led ______ disgrace,' the correct preposition is 'to' because the verb 'lead' takes the preposition 'to' when indicating a consequence. 'At', 'with', and 'in' do not fit this context. Therefore, 'to' is the correct answer.