; and (2) Congress should ensure that the value and scope of the deduction for charitable contributions is not diminished during a comprehensive reform of the tax code. 3. Determination of standard mileage rate for charitable contributions deduction (a) Determination of standard mileage rate for charitable contributions deduction Subsection (i) of section 170 of the Internal Revenue Code of 1986 is amended to read as follows: (i) Standard mileage rate for use of passenger automobile For purposes of computing the deduction under this section for use of a passenger automobile, the standard mileage rate shall be the rate determined by the Secretary, which rate shall not be less than the standard mileage rate used for purposes of section 213. . (b) Effective date The amendment made by this section shall apply to miles traveled after the date of the enactment of this Act. 4. Modification of substantiation requirements for charitable contributions (a) In general Paragraph (8) of section 170(f)(8) of the Internal Revenue Code of 1986 is amended by striking subparagraph (D) and by redesignating subparagraph (E) as subparagraph (D). (b) Effective date The amendments made by this section shall apply to contributions made in taxable years beginning after December 31, 2016. 5. Mandatory electronic filing for annual returns of exempt organizations (a) In general Section 6033 of the Internal Revenue Code of 1986 is amended by redesignating subsection (n) as subsection (o) and by inserting after subsection (m) the following new subsection: (n) Mandatory electronic filing Any organization required to file a return under this section shall file such return in electronic form. . (b) Inspection of electronically filed annual returns Subsection (b) of section 6104 is amended by adding at the end the following: Any annual return required to be filed electronically under section 6033(n) shall be made available by the Secretary to the public in machine readable format. . (c) Effective date (1) In general Except as provided in paragraph