sorry, (a)(ii) & (b)(ii) incorrect.

corrections ...

(a)(ii) at most 1 married couple
also must include cases where other then the 1 couple, the remaining 2 may also include single members of the other couples.

consider case of committee with 2 couples
ways = 3C2 = 3

then for committee with at most 1 couple
ways = 210 - 3 = 207
(easier to calculate as complement, because too many different possible cases, if calculate directly)

(b)(ii) one couple absent and others sit without restrictions
ways = 10P8/10 = 181440
(not necessary to divide by 2!)