(a) A Tier 3 member who meets the eligibility requirements of section 506 of the Retirement and Social Security Law, shall be eligible for an ordinary disability benefit if such member has been determined to be eligible for primary social security disability benefits.

(b) A Tier 3 member who meets the eligibility requirements of section 507 of the Retirement and Social Security Law shall be eligible for an accidental disability benefit if it is determined that such member was disabled as the natural and proximate result of an accident sustained in active service and not caused by the member, and if such member has been determined to be eligible for primary social security disability benefits.

(c) In lieu of the disability benefit set forth in subdivisions (a) and (b) of this section, a Tier 3 member who also meets the eligibility requirements of section 605 of the Retirement and Social Security Law may elect the disability benefit set forth in that section, to be determined in accordance with the provisions of section 5020.3 of this Part. However, in the event of such an election, the member will receive only the benefits provided under article 15 of the Retirement and Social Security Law, and may not mix the provisions of article 14 and article 15 to change the eligibility requirements for a benefit under either article.