The correct answer is: Only I is implicit.
The statement says that the company will not issue tender specifications to firms with a default rate of 25% or more. This implies that the company is concerned about the quality of performance of its suppliers and expects them to meet certain standards. However, the statement does not say anything about whether the company will be watching the quality of performance of its suppliers or whether it expects quality and professional approach from its suppliers. Therefore, only assumption I is implicit in the statement.
Assumption II is not implicit because the statement does not say anything about whether the company will be watching the quality of performance of its suppliers. The company may or may not be watching the quality of performance of its suppliers, but the statement does not provide any information about this.
Assumption III is also not implicit because the statement does not say anything about whether the company expects quality and professional approach from its suppliers. The company may or may not expect quality and professional approach from its suppliers, but the statement does not provide any information about this.