During which tenure did Ghulam Ishaq Khan serve as the Chairman of the Senate of Pakistan?

Ghulam Ishaq Khan was a prominent Pakistani bureaucrat and politician. He served as the Chairman of the Senate of Pakistan during the tenure of 1985-1988. Following this role, he went on to become the President of Pakistan in 1988 after the demise of General Zia-ul-Haq. The other options provided are empty, making 1985-1988 the only valid and correct period for his chairmanship of the Senate. This period was crucial in Pakistan's political landscape.