【单选题】
在下列函数中,( )在指定区域内是单调减少的函数
①
<img src=https://huaweicloudobs.ahjxjy.cn/087E58F5FC3F975668C0B235653FCD10.png title={KZ%~M7WDSN86IJUUVMFVK7.png alt={KZ%~M7WDSN86IJUUVMFVK7.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/44E8F1CC8CEFD9400C2FFE917B1F2D7D.png title=AX_S_DL_ZW}QZK]}]L`SP{7.png alt=AX_S_DL_ZW}QZK]}]L`SP{7.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/743F6FDBC8ECBD9A330B63164AFD4FF7.png title=F_M`]4_A]{N{~J$WD8C(Z9O.png alt=F_M`]4_A]{N{~J$WD8C(Z9O.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/7A6F6928A94857244FFE19169BD6C0F3.png title=VECWQKKE81JSICN(}}47RK5.png alt=VECWQKKE81JSICN(}}47RK5.png/>